Surely many drivers have faced the need to display the mileage on the speedometer for various reasons. Some found a way out of this situation by turning to specialists, while others were unable to solve the problem, although in fact everything is very simple.

Why shouldn’t you have a negative attitude towards increasing mileage?

Most car enthusiasts have a biased opinion towards those who decide to wind up the odometer. The fact is that unscrupulous sellers resort to rolling up the odometer, wanting to hide the true mileage in order to sell a used car at a higher price.

But it is worth noting that the mileage is reduced not only in the direction of decrease. There are objective situations that require increasing mileage:

The need to undergo maintenance at a service center ahead of schedule, for example, before a long trip.
Replacement of the dashboard, resulting in a failure of the odometer readings.
The need to check mileage due to engine replacement.
Installation of wheels of non-standard diameter, due to which the actual mileage does not correspond to the actual one.
Fair compensation for fuel costs.

Of course, there are times when you need to reduce your mileage. Indeed, for a careful owner, the excellent condition of the car does not always correspond to the true mileage, which is especially upsetting during the sale, when the buyer, seeing an impressive number on the speedometer, demands to lower the price. In this case, it is enough to simply check the mileage if the otherwise good technical condition of the car does not reveal its real age.

How to increase mileage?

Many car enthusiasts, even those who need to increase mileage for objective reasons, often refuse this procedure to the detriment of their own interests, although in fact, increasing mileage is absolutely safe for the car’s electronic systems.

You can wind the speedometer using a special device called a “winder”. The device is intended for calculating electronic speedometer readings on cars manufactured after 2006. Although if the car has an earlier year of manufacture, you can also choose a device to change the mileage.

The distinctive advantages of the device for winding up the speedometer can be considered:

The device does not require special installation.
Connects via a diagnostic connector directly inside the car.
Any car owner can use the speedometer winder, since the device is easy to operate.
The spinner has a compact size, so it can even be stored in the glove compartment.
The high winding speed of the speedometer can reach 5 thousand kilometers per hour.
The device is suitable for any brand of modern car, regardless of engine size or gearbox type.
Winding changes the mileage readings simultaneously in each duplicate block.

Tarnovsky V.N. et al. 21 How to increase tire mileage. Advice for car enthusiasts/V. N. Tarnovsky, V. A. Gudkov, O. B. Tretyakov. - M.: Transport, 1993. - PO with: ill., table. ISBN 5-277-01708-9 What tires are installed on passenger cars, how to choose tires for a particular car, what factors affect tire tread wear, how to repair a tire, perform quality maintenance and extend the life of a tire - you will find all this in this book. The book is intended for car enthusiasts.

Chapter 1. GENERAL INFORMATION ABOUT TIRES FOR PASSENGER CARS

Chapter 2. PERFORMANCE CHARACTERISTICS OF CAR TIRES

Chapter 3. FACTORS CAUSING INCREASED WEAR OF TIRES

Chapter 4. MAIN RESERVES FOR INCREASING THE SERVICE LIFE OF CAR TIRES.

PREFACE

More than 140 years have passed since the invention of the pneumatic tire, without which the very existence of a modern car is unthinkable. At first, this tire was intended not for a car, but for horse-drawn carriages, on which it replaced massive cast rubber tires (the so-called weight belts or rubber tires), and only many years after its appearance did the pneumatic tire find its practical application on cars.

Based on their intended purpose, car tires are divided into tires for cars and tires for trucks. For both cars, they use tires of diagonal and radial designs with and without tubes, single- and multi-layer (according to the number of cord layers), etc.

Tire manufacturers are constantly working to improve tire design, using modern materials, reducing the rubber content in the carcass, increasing cord strength, reducing carcass plies, creating tires with a low height and a wide profile width to improve vehicle stability and load-carrying capacity.

Improvement of tires is also aimed at increasing their service life, permissible loads, simplifying their production technology, increasing the safety of vehicles, improving their stability and controllability.

Until recently, most attention was paid to improving the design of bias-ply tires. Over the past 20 years, the weight of such tires has decreased by 20...30%, load capacity has increased by 15...20%, and service life has increased by 30...40%. Currently, the efforts of tire manufacturers are aimed at developing and improving the designs of radial tubeless single-ply tires made of steel cord, intended for mounting on semi-recessed rims with low flanges, as the most promising. Much attention is paid to the development of cordless tires made from a homogeneous rubber-fiber mass by extrusion or injection molding. Technical solutions for creating cordless tires will significantly simplify their production technology. These are the main directions in tire production.

How are things going with the tires? Numerous observations have shown that there are significant problems in this area, and the main one of these problems is the lack of necessary knowledge among the majority of car drivers. It is precisely because of ignorance that drivers fail to identify minor tire defects in a timely manner, overload vehicles beyond the established load capacity, do not comply with internal tire pressure standards, and do not carry out tire maintenance in a timely manner. The lack of qualified tire maintenance specialists leads to poor quality maintenance and repair, which significantly reduces the service life of the tires and increases the cost of operating the vehicle.

In order to improve the quality of tire operation, the scientific and technical center "Shinservice" was organized in 1991, the main task of which is to create numerous production and service enterprises for tires, as close as possible to consumers. Service will cover the full range of consumer needs. The functions of "Shinservice" include: organizing the supply of new tires, reconditioning worn tires, maintenance of new and reconditioned tires, wheel balancing, collection of end-of-life tires. In addition, the functions of Shinservice enterprises include such services as local repair of tubes and tires, adjustment of technical parameters of cars that affect the operation of tires, recommendations for the selection of tires taking into account the specifics of operation, the use of the reserve contained in the sub-groove layer of the tread by deepening grooves.

Information obtained as a result of tire service about the reasons for their failure to operate will make it possible to more clearly plan the timing of their maintenance and repair, and changes made to the design and materials of the tires will allow the necessary changes to be made in the technology of their maintenance and repair accordingly. Thus, the unified Shinservice system will unite the efforts of tire manufacturers, tire repairers and tire consumers - motorists. And all the efforts of Shinservice will be aimed at significantly increasing the mileage of tires and, consequently, reducing the cost of purchasing new tires, since the cost of timely retreaded tires by replacing the tread per 1 km of run is 2 times less than the cost of purchasing new tires. This is confirmed by the experience in servicing tires of the Omsk Tire Plant and Michelin "Michelin" (France), installed on 40 KamAZ vehicles of the Vladimir Production Association of Freight Road Transport. The vehicles were used for intercity transportation and for removing gravel from quarries. As a result of constant monitoring of air pressure standards in tires, timely and high-quality maintenance and repair, tire mileage was increased by 2...3 times. In addition, after additional deepening of the tread grooves, tire mileage was increased by another 20...50 thousand kilometers.

1.1. Car tire design

Most car tires consist of a rubber-cord casing - a tire, an airtight closed toroidal tube and a rim tape. In working condition, the chamber is filled with air under a certain pressure. Tubeless tires have a special sealing layer instead of a tube on the inside of the tire. The shock-absorbing capacity of a car tire is determined by the air pressure in the tire and the elasticity of the tire.

The design and material of tire elements are not always the same for different types of tires. Thus, passenger car tires differ from truck tires in the design of individual elements, overall dimensions and quality of materials used. They have a more elastic carcass, a lower height and greater dissection of the tread pattern, and smaller outer and landing diameters. However, passenger car tires, due to the greater permissible relative deformation, the greater number of loads per unit of distance traveled and high driving speeds, have a shorter service life compared to truck tires. Passenger car tires are designed primarily for use on higher category roads.

The tire has a complex configuration and consists of several structural elements (Fig. 1.1).

Fig.1.1. Tube tire:
1 - side tape; 2 - sidewall; 3 - layers of cord; 4 - breaker; 5 - protector; 6 - treadmill; 7 - frame; 8 - heel; 9 - tire bead; 10 - sock; 11 - wire ring; 12 - wing fastening strips.

Frame 7, being the main power part of the tire, limits the volume of the inflated chamber and absorbs the loads acting on the tire.

The main load on the tire is the vehicle's own weight and the weight of the cargo or passengers being transported. The frame must have significant strength, as well as a certain elasticity. It consists of several layers of rubberized cord and rubber layers - squidges - superimposed on each other. The strength of a tire is determined by the strength of the carcass and mainly depends on the strength of the cord, since its elastic modulus is several orders of magnitude greater than the elastic modulus of rubber.

The threads of adjacent layers of cord intersect each other at a certain angle and form a fabric consisting of a warp and a weft. Each thread is isolated from its neighbors and at the same time connected to them by rubber. Rubber protects the cord threads from moisture, chafing and promotes uniform distribution of loads between them.

Frame shape and number layers of cord 3 it is determined by calculation based on the specified air pressure, load, type and purpose of the tire. The cord threads bear the main load during tire operation, providing the latter with strength, elasticity, wear resistance and maintaining a given shape. The cord thread in a tire works mainly in tension and repeated bending. These stresses arise, as a rule, as a result of air pressure and the action of centrifugal forces, which create tensile stresses in the cord. The operation of the frame is significantly influenced by the thickness of the cord, its density, heat resistance and other physical and mechanical properties. Under the influence of forces applied to the wheel, the tire is deformed only in a certain section of the circle - the working zone, located in the area of contact of the tire with the road and equal to approximately one third of the circumference for both cars and trucks.

Breaker 4 A bias tire consists of a rubber-cord layer located between the carcass and the tread. It consists of two or more layers of sparse cord, interspersed with thicker layers of rubber. Thickened layers of rubber provide the ability to move the breaker cord threads during tire operation.

The design of the breaker depends on the type and purpose of the tire. The breaker is needed to strengthen the carcass and improve the connection between the carcass and the tread, which should be as strong as possible. The necessary connection is achieved by the correct selection of breaker material. Breaker rubber must ensure a smooth transition of stiffness from the carcass to the tread, which has a serious impact on the wear rate of the tire tread.

The breaker softens the effect of shock loads on the tire carcass, promotes a more uniform distribution of them over the surface of the tire, and absorbs multiple deformations in tension, compression and shear, which, however, leads to significant heat generation due to the insufficient thermal conductivity of rubber. Therefore, the breaker layer, as a rule, has a higher temperature (up to plus 120°C) compared to other elements of the tire.

Protector 5 is a thick profiled rubber located on the outside of the tire and comes into direct contact with the road when the wheel rolls. The tread provides the necessary service life of the tire, proper grip on the road, softens the impact of shocks and impacts on the tire carcass, reduces vibrations (primarily torsional) in the car transmission, and also protects the carcass from mechanical damage. As the wheel rolls, the tread elements work in bilateral compression and shear, as well as tension. These deformations are greater in absolute value than those of the frame and breaker.

The tread consists of a relief pattern and a sub-groove layer, which usually makes up 20...30% of the tread thickness. Too thin a sub-groove layer contributes to cracking of the tread, increased deformation of the cord threads of the first layer of the carcass, and a decrease in the strength of the carcass under the action of a concentrated load. An excessively thick layer worsens the cooling conditions of the tire, leading to overheating and delamination of the tire. The tread thickness varies across tires of different designs and purposes. The thicker the tread, the longer the mileage of the tires before it completely wears out, the better it protects the frame from external influences. However, a thick tread makes the tire heavier, leads to overheating and delamination, and increases the moment of inertia of the wheel and its rolling resistance. A thick tread causes increased heat generation at high speeds, when additional tread deformations appear as a result of a significant increase in inertial forces. The tread thickness of passenger car tires ranges from 7 to 12 mm, and for truck tires - from 14 to 22 mm.

The type of tread pattern depends on the type and purpose of the tire.

Car tires are made with different tread patterns. The pattern with longitudinal grooves has a fairly high tire grip on the road in the lateral direction and insufficient grip on wet and slippery roads in the longitudinal direction. Tread patterns with transverse grooves have opposite characteristics, so tread patterns that have longitudinal-transverse grooves are widely used.

Tires should not make noise when the vehicle is moving, especially on roads with improved surfaces. Tire noiselessness is achieved by choosing a specific tread pattern and using the principle of variable pitch of pattern elements along the circumference of the wheel.

The tread pattern has a great influence on the wheel's rolling resistance coefficient, tire wear and traction. Ensuring high wear resistance and the tire-road grip necessary for traffic safety and economical conditions is the main task of the tread pattern. Tread rubber must have high physical and mechanical properties, be durable, elastic, well resistant to abrasion, cuts, tears and repeated deformations, and also be resistant to aging.

The listed qualities of tread rubber are ensured by the appropriate choice of composition and technology for processing the rubber mixture.

Sidewall 2 is considered to be a rubber layer that covers the walls of the frame and protects it from mechanical damage and moisture. The sidewalls must be sufficiently elastic and, therefore, thin enough to withstand repeated bending for a long time and have little effect on the rigidity of the frame. They are made as one piece with the tread and from tread rubber compounds, although, depending on the operating conditions, cheaper compounds can be used for them.

The rigid part of the tire that serves to attach it to the wheel rim is called the bead. The tire fender consists of side ring 11, made of steel wire, solid profile rubber band (filler), bead ring wrapper and reinforcing tapes. A metal ring is necessary to give the board the necessary strength, and a rubber band contributes to the design of the board and its solidity. The bead ring and the rubber band are wrapped with a rubberized wrap. The shape of the bead ring affects the correct and reliable installation of the tire as a whole on the wheel rim. The number of metal wires in the bead ring and their diameter are determined by calculation.

The chamber is an annular tube made of airtight elastic rubber. It has a valve that serves to pump, hold and release air. The size of the tube must strictly correspond to the size and shape of the tire. The wall thickness along the cross section of the chamber is usually not the same. It is larger at the treadmill compared to the rim part. The tube itself could not withstand the internal pressure if it were not limited by the tire. When the wheel rolls in the area of contact of the tire with the road, the chamber experiences alternating deformation and operates under difficult temperature conditions. Rubber for inner tubes must be airtight, elastic, durable, well resistant to punctures and tears, resistant to thermal aging, and not change its dimensions and physical and mechanical properties over a wide range of ambient temperatures.

Each tire has a designation that characterizes its overall dimensions and type. The dimensions and markings of most tires are indicated on the sidewall of the tire and are indicated by a combination of two parameters: profile width (for example, 200 mm) and seat diameter (508 mm). The sizes of special tires are designated as a combination of outer diameter, section width and seat diameter. In the designation of radial tires, the letter R is placed after the second number, for example 200-508R. On products of foreign companies you can find the designation in inches and mixed (in inches and millimeters). In the first case, both numbers conventionally indicate tire sizes in inches, for example, 7.50-20; 5.20-13, in the second case, the first number indicates the tire profile width in millimeters, and the second number indicates the wheel rim diameter in inches, for example, 260-20.

During manufacturing, each tire is marked with the trademark of the tire manufacturer.

During manufacturing the following is applied to each inner tube and rim tape:
trademark of the manufacturer, camera size, month and year of manufacture, stamp of the technical control department.

On the sidewall or shoulder area of each tire restored by applying a new tread, apply:
tire serial number;
name or trademark of the company that retreaded the tire;
restoration date (year, month);
stamp of the technical control department of a tire repair company;
balancing mark (for tires that have been balanced).

On each retreaded tire, if the markings are lost, the tire designation, model, ply rating or load capacity index are again applied.
For example:

Passenger tire marking 165/80R13 MI-166 Steel Radial 82S Tubeless 168Я502311:
where 165/80R13 is the designation (size) of the tire (165 is the tire profile width, mm; 80 is the series index; R is the distinctive index of the radial tire; 13 is the tire mounting diameter in inches);
MI-166 - tire model (MI - symbol of the tire developer: M - Moscow Tire Plant; I - Research Institute of the Tire Industry; 166 - serial number of development);
Steel - designation of steel cord in the breaker;
Radial - radial tire;
82 - load capacity index;
S - index of the maximum permissible speed, in this case 180 km/h;
Tubeless - tubeless tire (tube type is designated Tube type);
168Я502311 - serial number of the tire (168 - date of manufacture: 16 - serial number of the week from the beginning of the year, 8 - last digit of the year of manufacture - 1978; I - index of the tire manufacturer - Yaroslavl Tire Plant;
502311 - serial number of the bus).

Truck constant pressure tire marking 260R508 (9.00R20) I-N142B NS-12 GOST 5513-86 NKH1771395:
where 260R508 (9.00R20) is the tire size designation;
I-N142B - designation of the tire model (I-N - designation of the tire developer, here - Research Institute of the Tire Industry;
142 - development serial number; B - version 142 development);
NS-12 - tire ply standard (a symbol for the strength of the carcass of a given tire, determining its compliance with the maximum permissible load);
GOST 5513-86 - designation of the standard according to which the tire is manufactured;
NKH1771395 - symbol of the serial number (NK - index of the tire manufacturer, here - Nizhnekamsk Tire Plant; XI - month of tire manufacture - November, 77 - last two digits year of tire manufacture;
those. 1977, 1395 - serial number of the tire).

Dimensions of wide-profile, arched tires and pneumatic rollers are given in millimeters only. Wide-profile tires and pneumatic rollers are designated by three numbers. The first number means the outer diameter of the tire, the second - the width of its profile, the third - the diameter of the rim. A multiplication sign is placed between the first two digits, a dash is placed between the second and third, for example, 1600x600-635. Arched tires are indicated by two numbers connected by a multiplication sign; The first number characterizes the outer diameter of the tire, the second - the width of the tire profile.

An arrow is placed on the sidewall of tires with a directional tread pattern indicating the direction of rotation of the wheel. The letter M, applied in paint, indicates the tire's frost resistance, and the yellow ring indicates that it is intended for use in tropical climates. For passenger car tires, the point may be marked with a red circle, triangle or square.

When mounting a tire, this place is located near the hole in the wheel rim for the inner tube valve.

1.3. The design of passenger car wheels.

The wheel is an integral part of the car, so its design must be closely consistent with the design of the car's chassis and meet the requirements dictated by its operating conditions. In this regard, wheels of various designs and sizes are used for cars, trucks, specialized vehicles and buses. Wheels are usually divided according to their belonging to one or another type of rolling stock, the type of tires used, the design of the disk and rim, and the wheel manufacturing technology.

Every wheel, as a rule, consists of two main parts: disk 1 with rim 2 (Fig. 1.2) and a tire. Depending on the type of vehicle, wheels are divided into three groups: for passenger cars, for trucks, including buses, and for special-purpose vehicles.

Fig.1.2. Wheel of a GAZ-24 "Volga" car:
a - wheel design; b and c - profiles of landing flanges for tubeless tires; g - symmetrical rim profile; 1 - stiffeners; 2 - rim; 3 - disk; 4 - profiled part of the disk.

For passenger cars, wheels with deep one-piece rims are mainly used (see Fig. 1.2). The disc is attached to the rim by welding or, less commonly, by rivets. To ensure strength, the disc is given a special configuration that increases its rigidity. Rims for passenger car wheels are mainly made with inclined (conical) flanges. The inclination of the shelves is assumed to be 5°.

For passenger cars, the most widely used wheels are those with rim flange diameters of 15, 14 and 13 inches with a rim profile width of 4...7 inches. Passenger car wheel rims have a complex configuration and are made by stamping from sheet metal, which gives it the necessary rigidity.

Wheels are usually designated by the main dimensions (in inches or millimeters) of the rim, namely the width and diameter of the landing flanges. After the first number or group of numbers, a letter of the Latin or Russian alphabet is placed, characterizing a set of sizes that determine the profile of the side flange of the rim (A, B, etc.).

1.4. Tire technical characteristics.

Tires are characterized by purpose, sealing method, type, design and tread pattern. As mentioned earlier, depending on the purpose, tires for cars and trucks are distinguished. Passenger car tires are used on passenger cars, light trucks, minibuses and their trailers. Based on the sealing method, tires are divided into tubed and tubeless. By design (by the construction of the frame), diagonal and radial tires are distinguished (Fig. 1.3). According to the configuration of the cross-sectional profile (depending on the ratio of the profile height to its width) - regular profile tires, wide-, low- and ultra-low profile.

Rice. 1.3. Tires of diagonal (a) and radial (b) design (section):
1 - protector; 2 - broker layer; 3 - frame layer; 4 - rubber layer of the frame; 5 - side part.

road pattern (Fig. 1.4, a) - checkers or ribs, dissected by grooves. Tires with a road tread pattern are designed for use primarily on roads with improved surfaces; directional pattern (Fig. 1.4, b) - asymmetrical relative to the radial plane of the wheel.
A tire with a directional pattern is used for use in off-road conditions and on soft soils; all-terrain tread pattern (Fig. 1.4, c) - high lugs separated by grooves. Tires with this tread pattern are intended for use in off-road conditions and on soft soils; quarry pattern (Fig. 1.4, d) - massive protrusions of various configurations, separated by grooves;
winter tread pattern (Fig. 1.4, d) is a pattern where the protrusions have sharp edges. Tires with this pattern are designed for use on snowy and icy roads and can be equipped with anti-skid studs;
universal pattern (Fig. 1.4, e), checkers or ribs in the central zone of the treadmill and lugs along its edges. Tires with this tread pattern are designed for use on roads with improved lightweight surfaces.

Rice. 1.4, a Road tread pattern.

Rice. 1.4, b Directional all-terrain tread pattern.

Rice. 1.4, c All-terrain tread pattern.

Rice. 1.4, d Winter all-terrain tread pattern.

Rice. 1.4, e Universal tread pattern.

The classification of tires by purpose is important, as it determines the basic requirements for the tire design.

A tube tire has a complex configuration and consists of many structural elements: carcass, belt, tread, sidewall, beads and a tube with a profile height to width ratio of more than 0.80 (see Fig. 1.1).

In diagonal tires, the cord threads of the carcass and breaker intersect in adjacent layers, and the angle of inclination of the threads in the middle of the treadmill in the carcass and belt is 45...60°.

A tubeless tire is almost no different in appearance from a standard car tire (Fig. 1.5). The difference from standard tires is sealing layer 1 (airtight) on the inner surface of the tire and sealing layer 2 on the outer surface of the beads.

Rice. 1.5. Tubeless tire (cut):
1 - tire; 2 - sealing layer; 3 - rim; 4 - valve.

Tubeless tires have a slightly smaller mounting diameter relative to the rim mounting diameter, a special shape and bead design that ensures a tighter fit of the tire on the wheel rim in the presence of air pressure inside the tire. Tubeless tires with a self-sealing inner layer and radial ribs on the sidewalls for cooling the tire are produced abroad.

Cords for tubeless tires are made mainly from viscose, nylon and nylon. Tubeless tires have sealed rims. Valve 3 with sealing rubber washers is attached directly to the wheel rim. A special feature of tubeless tires is that their frame is constantly exposed to compressed air, which leaks through the sealing layer of the tire during operation. In these cases, the air in the tire carcass creates tension between the individual elements of the tire and causes delamination. Therefore, to eliminate this harmful phenomenon, tubeless tires have special drainage holes through which the air penetrating into the frame is vented out.

The main advantage of tubeless tires is increased vehicle safety at high speeds compared to tubed tires. A tubeless tire consists of one monolithic part, so air from the cavity can only escape through the puncture hole, and the internal pressure decreases slowly, so that the driver can drive with the damaged tire to the repair site. It should be noted that there is better heat dissipation directly through the metal rim of a tubeless tire, the absence of friction between the tire and the tube and, as a result, a lower temperature regime of the operating tire.

Tubeless tires are also characterized by greater stability of internal air pressure, which is explained by the fact that air leaks through the unstretched airtight layer of a tubeless tire with greater difficulty than through the stretched walls of the tube. Tubeless tires are less subject to dismantling and mounting during operation, since minor damage can be repaired without removing the tire from the rim.

Tubeless tires, which are interchangeable with tubed tires, can be mounted on standard deep rims as long as they are sealed, i.e., free of dents and damage.

The warranty mileage standards for tubeless tires are the same as for tubeless tires, however, the operating experience of tubeless tires shows that their durability is 20% higher than the durability of tubeless tires, which is explained by the better temperature conditions of the tires and the constant internal air pressure in them. However, their production requires high-quality materials, but they are less technologically advanced. Operating tubeless tires requires high technical culture.

Radial tires with metal cord are produced in three types: with metal cord in the carcass and belt, with nylon cord in the carcass and metal cord in the belt, with a meridional arrangement of steel or nylon cord threads in the carcass and metal cord in the belt (Fig. 1.6).

Rice. 1.6. Tire type R with steel cord broker:
1 - frame; 2 - breaker layers.

Steel cord tires have a wider bead opening than conventional tires. The ends of the cord layers are wrapped in pairs around one or two bead rings wound from the same wire. On the inside of the frame in the treadmill area, steel-cord tires have a vulcanized rubber layer. It serves to protect the tube from punctures and more evenly distribute stress in the tire body and in the treadmill area.

Metal cord, having high thermal conductivity and heat resistance, helps reduce stress and more uniform temperature distribution in the tire body. The service life of steel-cord tires when used in various road conditions is approximately 2 times longer than that of conventional tires used in similar conditions.

The nylon cord in the carcass and the metal cord in the breaker make it possible to increase the strength of the tire in the treadmill area, reduce the temperature in the most stressed points of the tire, protect its carcass from damage, and prevent the spread of cracks in the tread.

The meridional arrangement of the carcass cord threads increases the elasticity of the tire, increases the tire's grip on the road, and significantly reduces wheel rolling losses. The metal cord of the breaker increases the strength of the carcass in the circumferential direction and improves the temperature conditions of the tire. Such tires work successfully on roads with improved surfaces and in off-road conditions at high speeds.

Frost-resistant tires are designed for use in areas with temperatures below minus 45 °C. Operating vehicles in these areas on regular non-frost-resistant tires is not permitted by current regulations. tire operating rules. Frost-resistant tires are made from rubber that retains sufficient strength and elasticity at low temperatures and ensures normal tire service life in the specified areas.

Tires for tropical climates are distinguished by the fact that they are made of heat-resistant rubber, which retains its strength and elasticity well at high speeds and high ambient temperatures characteristic of countries with a tropical climate. These tires have a frame made of nylon or high-strength or ultra-strong viscose cord.

Tires with metal studs are used to improve the stability and handling of cars, trucks and buses on slippery, icy roads and on ice. Diagonal and radial tires can be equipped with studs in the tread. The use of these tires reduces the vehicle's braking distance by 2...3 times, improves acceleration by 1.5 times and dramatically increases the vehicle's stability against skidding.

Low- and ultra-low-profile tires are available for cars, trucks and buses. They have a reduced profile height (for low-profile H/V = 0.7-0.88; for ultra-low-profile H/V‹0.1 where H is the profile height; B is the profile width), which increases the stability and controllability of the vehicle, and has greater load capacity and cross-country ability.

2.1. Interaction of the tire with the road.

When driving a car, the tire operates in very difficult and difficult conditions. During the rolling process, forces of varying magnitude and direction act on the tire. Dynamic forces, as well as forces associated with the redistribution of the vehicle’s mass between the wheels, are added to the internal air pressure and the action of the vehicle’s mass on the tire in a stationary state when the wheel is rolling. The forces change their meaning, and in some cases their direction, depending on the speed and condition of the road surface, ambient temperature, slopes, the nature of the road turns, etc.

Rice. 2.1. Action of forces on a stationary wheel.

Under the influence of forces during wheel rolling, the tire is continuously deformed in various zones, i.e. its individual parts bend, compress, stretch. When driving for a long time, the tire heats up, as a result of which the internal air pressure in the tire increases and the strength of its parts, especially rubber, decreases.

The forces and moments acting on the wheel of a car cause reactive forces from the road, which are generally located in three mutually perpendicular directions and are applied to the wheel at the point of its contact with the base of the road. These reactive forces are called vertical, tangential and lateral. A stationary wheel is subject to the action of one vertical force G from the weight of the car applied to the axis of the wheel and an equal reactive force Z from the road. The vertical force G applied to the wheel axis and its reaction Z from the road are located in the same vertical plane passing through the wheel axis.

In the case of a driven wheel (Fig. 2.2), the pushing force P from the car is transmitted through the bearing to the wheel axle and causes a tangential reaction X from the road, which is applied to the surface of the wheel in the zone of its contact with the road and has the opposite direction to the pushing force P.

V - movement speed

The rolling of the driven wheel along the supporting surface leads to a violation of symmetry in the area of contact of the wheel and the road relative to the vertical passing through the center of the wheel, and causes a displacement of the reaction Z relative to this vertical forward along the direction of movement of the wheel by a certain amount a, called the friction coefficient and measured in units of length . The vertical reaction Z, as with a stationary wheel, is numerically equal to the load.

The operation of the driving wheel differs from the operation of the driven wheel in that not a pushing force is applied to the driving wheel, but a torque Mk (Fig. 2.3, a). This moment must balance the total resistance Rsopr of all forces opposing the movement (wind, road slope, friction, inertial). As a result, in the contact of the wheel with the road, a reaction occurs Rх = Рсор, directed in the direction of movement.

In addition to the driven and driven functions, the wheel can perform a braking function. The work of the braking wheel can be compared with the work of the driving wheel. The difference is that the braking torque, and therefore the tangential reaction of the road, have the opposite direction and are determined by the intensity of braking (Fig. 2.3, b). The coefficient of adhesion between the wheel and the road surface is in most cases significantly less than unity, and therefore the tangential force is usually significantly less than the vertical force.

Rice. 2.3. Forces acting on the driving (a) and braking (b) wheels.

In addition to the listed forces, the wheel is often subject to lateral forces and moments resulting from the action of overturning lateral forces on the vehicle chassis, for example, centrifugal force when turning or a mass component due to the inclination of the road. On a convex or concave road profile, as well as when driving on a road with uneven surfaces, the wheels can also experience lateral forces (Fig. 2.4), which, provided they are equal on the left and right wheels in magnitude and opposite in direction, will be damped on the axle , without being transmitted to the car itself. The effect of lateral force on the wheel is limited by the adhesion of the wheel to the road. When a vehicle moves along a convex or concave road profile, or especially along a road with uneven surfaces, lateral forces can reach very significant values.

vertical reaction Z, the value of which is determined by the total mass of the transported cargo and vehicle. This load always acts on the wheel, regardless of whether it is moving or not, working as a driven, driving or braking wheel. The value of this load when driving can vary depending on acceleration (deceleration), longitudinal and transverse profile of the road, its tortuosity, unevenness of the road surface and speed;
a tangential reaction located in the plane of the wheel (not shown in Fig. 2.4) and resulting from the application of an external moment (torque or braking), pushing force, aerodynamic drag, and rolling friction force to it. The value of this reaction usually reaches its greatest value during braking, however, as a rule, it is limited by the coefficient of adhesion of the wheel to the road surface, which in most cases is less than unity and, therefore, even the largest value of the tangential reaction is, as a rule, less than the vertical reaction;
lateral reaction Y, which is located in a plane perpendicular to the plane of the wheel. Like the tangential reaction, this reaction is also limited by the adhesion force between the wheel and the road, and, therefore, its maximum value cannot be greater than the vertical force, except when driving on an uneven road or deep rut. Under these conditions, the lateral reaction can significantly exceed the traction force of the wheel and the road.

Rice. 2.4. The action of forces on the wheels while driving on an uneven surface.

Of particular interest are the rolling of a tilted wheel and the sideways slip of a tire. When a car moves around a turn, the profile of the elastic tire is deformed in the lateral direction under the action of centrifugal force directed perpendicular to the plane of the wheel (Fig. 2.5). Due to the lateral deformation of the tire, the wheel does not roll in the I-I plane, but with some slip.

Rice. 2.5. Deformation of the tires when the car turns and the corresponding distortion of the contact patch of the tire with the road due to wheel slip (type A).

The ability of a tire to undergo lateral deformation has a great influence on the performance properties of the vehicle, especially its stability and handling. Therefore, the parameters that determine wheel slip are an important characteristic of the tire.

Wheel slip is assessed by the angle d, which is commonly called the lateral slip angle. Forces applied to the wheel cause lateral deformation of the tire as a result of the tread bending laterally. When the wheel rolls with slip, the tire has a complex deformation that is asymmetrical relative to its vertical plane of symmetry.

For each tire there is a certain maximum lateral force and a corresponding maximum slip angle, at which there is still no significant slipping of the tread elements in the lateral direction. The maximum angle for most domestic passenger car tires is 3...5°.

One of the most common cases of wheel rolling is when it moves with an inclination towards the road. Indeed, on a car, the wheels may be inclined towards the road due to the use of independent suspension, the slope of the road and other factors.

The inclination of the wheel to the road has a significant impact on the tire's performance and trajectory. When an inclined wheel rolls in the plane of rotation from the side of the road, it is also subject to lateral force and torque. The latter tends to turn the wheel in the direction of its inclination. The inclination of the wheel to the road leads to lateral deformation of the tire, as a result of which the center of contact of the wheel with the road shifts towards the inclination of the wheel. On an inclined wheel, the tire tread wears out quickly and unevenly, especially in the shoulder area on the inclined side of the wheel. Thus, tilting the wheel toward the road significantly reduces tire life.

The inclination of the wheel to the road changes the slip angle. When the car moves around a turn, when the wheel tilts towards the lateral force due to the lateral tilt of the body, wheel slip increases. This phenomenon is observed on the front steered wheels of passenger cars with independent suspension. Reducing the tendency of tires to slip sideways and reducing the inclination of the wheel to the road has a positive effect on. extending tire life.

2.2. Energy losses due to tire rolling.

A pneumatic tire, due to the presence of compressed air in it and the elastic properties of rubber, is capable of absorbing huge amounts of energy. If a tire, inflated to a certain pressure, is loaded with an external force, for example vertical, and then unloaded, then you can notice that when the tire is unloaded, not all the energy will be returned, since part of it spent on mechanical friction in the tire materials and contact friction is irreversible losses.

When a wheel rolls, energy is lost due to its deformation. Since the energy returned when the tire is unloaded is less than the energy expended on its deformation, in order to maintain uniform rolling of the wheel it is necessary to constantly replenish energy losses from the outside, which is done by applying either a pushing force or torque to the wheel axis.

In addition to the resistance resulting from losses associated with tire deformation, the moving wheel experiences resistance due to friction in the bearings, as well as air resistance. These resistances, although insignificant, also belong to the category of irreversible losses. If the wheel moves along a dirt road, then, in addition to the losses listed above, there will also be losses due to plastic deformation of the soil (mechanical friction between its individual particles).

Rolling losses are also assessed by the strength of rolling resistance or the power of losses due to it. The rolling resistance of a wheel depends on many factors. It is largely influenced by the design and materials of the tire, driving speed, external loads and road conditions. Losses due to rolling resistance of the driven wheel when driving on paved roads consist of losses due to various types of friction in the tire. These losses consume a significant portion of engine power. The energy absorbed by the tire causes its temperature to rise significantly.

Rolling resistance is highly dependent on rolling speed. In real operating conditions, rolling resistance can increase by more than 2 times. In Fig. Figure 2.6 shows the test results when the tire had a normal load of 375 kgf and the corresponding air pressure of 1.9 kg/cm2. The tests were carried out on a drum stand at a steady thermal state of the tire. In Fig. 2.6, three clearly defined zones of increasing rolling resistance force are visible. At very low speeds (at the beginning of zone I), power losses due to rolling are minimal. These losses are caused by compression of the rubber in the area of contact between the tire and the road.

Rice. 2.6. Dependence of the rolling resistance force Pk of a 6.45-13R tire model M-130A with a steel cord breaker on the speed V.

In zone II, as speed increases, losses increase, and the inertial forces of wheel movement begin to affect themselves more and more. Starting from a certain speed value, the deformation of the tire elements increases significantly, which characterizes the rolling processes in zone III.

An increase in air pressure in a tire leads to a reduction in rolling losses of the tire on a hard surface over the entire range of speed changes, a decrease in radial deformation and an increase in its rigidity, which reduces heat losses. It must be remembered that during the rolling process, as the tire heats up, the air pressure in it increases and the rolling resistance decreases. Warming up a cold tire to a steady operating temperature reduces the rolling resistance coefficient by approximately 20%. The dependence of rolling resistance on air pressure is an important characteristic of a tire.

Increasing the load on the wheel at constant air pressure in the tire increases the rolling resistance force. However, when the load changes from 80 to 110% of the nominal value, the rolling resistance coefficient remains practically constant. An increase in load by 20% above the maximum permissible increases the rolling resistance coefficient by approximately 4%.

The rolling resistance of a wheel increases slightly with increasing torque and braking torque applied to the wheel. However, the intensity of the increase in losses during braking torque is greater than during driving torque.

For different types of road surfaces, the rolling resistance coefficient varies within the following limits:

in a good condition............................................... ..................................... 0.015...0.018
in satisfactory condition................................................... ................... 0.018...0.020

Gravel road in good condition.................................... 0.020...0.025

dry, rolled ................................................... ........................................... 0.025.. .0.035
after the rain................................................ ........................................................ .. 0.050...0.150
into the mud......................................................... ........................................................ ...0.10.....0.25

dry................................................. ........................................................ ............ 0.100...0.300
raw................................................. ........................................................ .......... 0.060...0.150

Icy road and ice.................................................... ........................... 0.015...0.03

Rolled snow road................................................... ........................ 0.03.....0.05

On paved roads, the rolling resistance of a wheel largely depends on the size and nature of the road irregularities. Driving resistance under such conditions decreases with increasing wheel diameter.

When driving on soft dirt roads, rolling resistance depends on the degree of deformation of the tire and the ground. The deformation of a conventional tire on these soils is approximately 30...50% less than on hard surfaces. For each tire size and driving conditions, there is a specific air pressure that provides minimum driving resistance.

2.3. Tire grip properties.

The ability of a normally loaded wheel to perceive or transmit tangential forces when interacting with the road is one of its most important qualities that contribute to the movement of the car. Good adhesion of the wheel to the road increases controllability, stability, braking properties, i.e. traffic safety. Insufficient traction, as statistics show, is the cause of 5...10% of traffic accidents when driving on dry roads and up to 25...40% on wet roads. This quality of the wheel and road is usually assessed by the adhesion coefficient Ф - the ratio of the maximum tangential reaction Rx max in the contact zone to the normal reaction or load G acting on the wheel, i.e. Ф=Rx max/G.

There are three coefficients of adhesion: when the wheel rolls in the plane of rotation without slipping or skidding (sliding); when slipping or skidding in the plane of rotation of the wheel; when the wheel slips sideways.

Increasing the coefficient of adhesion can be achieved at the expense of other qualities of the tire. An example of this is the desire to increase grip on wet roads by dividing the tread pattern, which reduces the strength of the tread elements.

Taking into account climatic and road conditions, a number of countries have established minimum friction coefficient values in the range of 0.4...0.6. The coefficient of adhesion depends on the tire design, inflation pressure, load and other operating conditions, but mostly on road conditions. The range of variation of this coefficient depending on the tire design is different for different road conditions. When driving on hard, flat, dry roads, the adhesion coefficients of tires with various structural elements are close, and their absolute values depend mainly on the type and condition of the road surface and the properties of the tread rubber. The tread pattern has the greatest impact on traction under these conditions. Increasing the richness of the tread pattern usually increases traction. The influence of the tread pattern is very large when the tire rolls on smooth surfaces. Tread dissection improves the tire's grip on wet surfaces due to better displacement of water from the contact area, as well as due to increased pressure. The acceleration of the release of water from the contact area is facilitated by the expansion of the grooves, their straightening, and a decrease in the width of the protrusions. Traction improves with longer knobs of the tread pattern, and the lowest coefficient of traction is observed with square and round knobs. Slot-shaped grooves do not have large flow sections, but they create significant pressure at the edges and, as it were, wipe the road. When moisture is removed, dry and semi-dry friction conditions arise, which sharply increases the adhesion coefficient. When the height of the tread pattern lugs decreases, the removal of water from the contact zone slows down due to a decrease in the flow areas of the grooves and, accordingly, the grip of the tire with the road deteriorates.

The type of tread pattern also has a significant impact on the grip of tires on wet roads. With a longitudinal tread pattern orientation, aquaplaning* occurs at a lower speed and with a smaller water wedge thickness than in the case of a transverse tread pattern orientation.

Of great importance, especially at high speeds, is the thickness of the water layer on the surface of the coating. At speeds over 100...120 km/h and a water layer thickness of 2.5...3.8 mm, even an unworn tread with full-height lugs does not ensure water removal from the contact area with the road (adhesion coefficient is less than 0.1).

When driving on soft soils, tire traction depends on surface friction with the ground, the shear resistance of the soil pinched in the depressions of the pattern, and the depth of the rut. The design parameters of the tread pattern are of great importance for the adhesion of the tire to the road when the soil is heterogeneous and when there is a softer layer in the upper part and relatively hard soil in the lower part.

When driving on soft, viscous soils, traction depends to a greater extent on the self-cleaning ability of the tread pattern, which can be assessed by the speed of rotation of the wheel, at which soil is thrown out of the depressions of the pattern by centrifugal force. Self-cleaning ability is influenced by factors related to soil properties and tire parameters.

A recently common way to increase tire grip in winter is to use metal studs. However, on roads cleared of snow and ice, the use of tires with studs is impractical; here tires with a winter tread pattern have an advantage.
*Hydroplaning- The appearance of a water wedge between the tire of a moving car and the road, sharply reducing the adhesion of the wheel to the road.

2.4. Load capacity and shock-absorbing properties of tires.

The vehicle's carrying capacity must correspond to the carrying capacity of its chassis, one of the most important elements of which is the tire. Under the influence of a normal load applied to the wheel, the tire is deformed. This occurs with a slight increase (1...21) of the internal air pressure in the tire, since the volume of air practically does not change when the tire deforms. But, despite such a slight increase in the internal air pressure in the tire, the work of air compression during its deformation is quite significant and, at nominal load and pressure, amounts to approximately 60% of the total work of deformation. The remaining 40% is spent on deformation of the tire material, of which about a third is due to tread deformation.

With an increase in normal load at a given internal pressure, the value of the air compression force decreases.

Under the influence of load, the distance from the wheel axle to the road is reduced due to a decrease in height and an increase in the width of the tire profile. The value by which the height of the tire profile changes under load when resting on a plane is usually called normal deformation, and deformation at any point of the tread in the direction of the wheel radius is called radial deformation at a given point of the tire.

Normal deformation depends on the size and design of the tire, the material from which it is made, the width of the rim, the hardness of the road surface, the air pressure in the tire, the normal load, the values of the circumferential and lateral forces applied to the wheel. It characterizes the degree of loading of the tire, its load capacity and durability.

The load capacity is also determined by the design parameters of the tire, mainly overall dimensions, internal pressure, number of layers and type of cord in the carcass, profile. An increase in load capacity (but within limited limits) is achieved by increasing the internal pressure in the tire, at which its deflection decreases. However, as the pressure increases, it is necessary to increase the tire ply, which entails undesirable phenomena.

2.5. Durability, wear resistance and tire imbalance.

The durability of a car tire is determined by its mileage up to the maximum wear of the tread pattern lugs - a minimum lug height of 1.6 mm for passenger car tires and 1.0 mm for truck tires. This limitation was adopted for reasons of traffic safety and protection of the tire carcass from damage in the event of wear of the sub-groove layer. Tire longevity depends on the tire's internal air pressure, the mass load on the tire, road conditions and vehicle driving conditions.

Tread wear resistance is determined by the intensity of tread wear, i.e. wear related to a unit of mileage (usually 1 thousand km), under certain road and climatic conditions and driving modes (load, speed, acceleration). The wear rate Y is usually expressed as the ratio of the decrease in height h (in mm) of the tread lugs over a mileage to this mileage
Y=h/S, where S is mileage, thousand km.

Tread wear resistance depends on the same factors as tire longevity.

Unbalance and runout of wheels increase vibration and make driving difficult, reduce the service life of tires, shock absorbers, steering, increase maintenance costs, and worsen traffic safety. The effect of wheel imbalance and runout increases with vehicle speed. The tire has a significant impact on the total imbalance of the car, since it is the most distant from the center of rotation, has a large mass and a complex design.

The main factors influencing tire imbalance and runout include: uneven tread wear across the thickness and uneven distribution of material around the circumference of the tire.

Research conducted at NAMI shows that the most unpleasant consequences of imbalance and runout of wheels and tires assemblies are vibrations of the wheels, cab, frame and other parts of the car. These vibrations, reaching a maximum value, become unpleasant for the driver, reduce the comfort, stability, and controllability of the car, and increase tire wear.

Static imbalance of the hub assembly with the front wheel brake drum, kgxcm .... 0,250
Stud circle runout, mm .............................................................................................. 9,25
Radial runout of the rim seating surface, mm ............................................................. 1,2
Lateral runout of rim flanges, mm ............................................................................................ 1,0
Static imbalance of wheel without tire, kgxcm....................................................................... 0,250
Radial runout of the tire, mm ..................................................................................................... 1,0
Lateral " ", mm ......................................................................................................................... 1,0
Static tire imbalance, kgxcm ........................................................................................ 0,850
Static imbalance of wheel and tire assembly, kgxcm ......before balancing:...............................1,75**;1,9**;
after balancing:......................................... 0,26***; 0,26***

** Up to the specified values they are not balanced, above - they are balanced, but not more than 2...3 weights.
*** For passenger cars of the domestic market, the imbalance of the wheel assembly with the tire before balancing is accepted to be no more than 3.6 kg x cm.

3.1. Types of tire wear and destruction

The task of preventing premature wear and tear of tires is very complex and is associated with the ability to identify their types and accurately identify the cause that caused each specific tire failure.

All tires that are out of service are divided into two categories: with normal wear and with premature wear (or tire destruction). Normal wear or destruction of new and initially retreaded tires is considered to be natural wear that occurs when the tire meets its operational mileage standard and does not exclude its retreading. Normal wear or destruction of a retreaded tire is considered to be wear that occurs after it has completed its operational mileage standard, regardless of the suitability or unsuitability of this tire for subsequent retreading. Tires with wear and tear that do not meet the specified criterion belong to the 2nd category (prematurely worn out).

Tires with category 1 wear are divided into two groups: suitable for retreading, which includes new and previously retreaded tires, and unsuitable for retreading, which includes only tires retreaded more than once.

Tires with category 2 wear are also divided into 2 groups: with wear (destruction) of an operational nature and with a manufacturing defect. Wear (or destruction) of a production nature is divided, in turn, into two groups: manufacturing defects and restoration defects.

A detailed study of the types of wear and damage of tires will provide a full analysis of the reasons for their premature failure and implementation of measures that increase the use of tire life. Proper use of tires and systematic care of them are the main conditions for increasing their service life. According to NIISHPA and NIIAT, about half of tires fail prematurely due to violation of operating rules. Let's consider the main reasons affecting the reduction in tire service life.

3.2. Failure to comply with internal air pressure standards in tires and their overload.

Pneumatic tires are designed to operate at a specific air pressure. It should be borne in mind that the materials from which the tire is made are not completely sealed, so air gradually leaks through the walls of the chamber, especially in the summer, and the air pressure decreases. In addition, the cause of insufficient air pressure may be damage to the tube or tire (tubeless), leakage of the valve spool and parts securing it to the rim (for tubeless tires), or untimely checking of the air pressure. You cannot judge the internal pressure in a tire “by eye” or by the sound when you hit the tire, since you can make a mistake by 20...30%.

Tires with reduced internal pressure have increased deformation in all directions and, therefore, when rolling, their tread is more prone to slipping relative to the road surface, resulting in severe tire tearing. In this case, their elasticity is lost, and their strength drops sharply. As a result, tire life is reduced.

The result of working with low air pressure in the tire may be the tire turning on the rim, causing the inner tube valve to come off or be destroyed in the area where the valve is attached. With reduced pressure, the rolling resistance of the wheels increases, and as a result, fuel consumption increases significantly. An accidental significant decrease in air pressure in a tire can be promptly detected by increased deformation of the tire, the vehicle pulling towards the tire with low pressure and deterioration in handling. In this case, the tires quickly become overloaded and wear out. With reduced air pressure, tire stiffness decreases and internal friction in the tire sidewalls increases, which leads to an annular fracture of the carcass.

A ring fracture is a tire damage in which the threads of the inner cord layers lag behind the rubber, fray and tear along the entire circumference of the side walls. A tire with an annular frame fracture cannot be repaired. An external sign of a ring fracture is a dark stripe on the inner surface of the tire, running along the entire circumference. This strip indicates the beginning of the destruction of the cord threads. It is strictly forbidden to drive a car on completely deflated tires, even over a distance of several tens of meters, as this causes severe damage to tires and tubes that cannot be repaired.

Increased air pressure also reduces tire life, but not as dramatically as lower pressure. With increased air pressure, stresses in the frame increase. At the same time, the destruction of the cord accelerates, the pressure increases when the tire interacts with the road, leading to intensive wear of the middle part of the tread. The tire's shock-absorbing properties are reduced and it is subjected to greater shock loads. The impact of a wheel on a concentrated obstacle (stone, log, etc.) leads to a cross-shaped rupture of the tire frame, which cannot be restored.

At normal air pressure in the tire, tread wear is distributed evenly across its width. With an increase in internal air pressure by 30%, the wear rate is reduced by 25%. In this case, there is an increase in wear in the middle of the tire tread in relation to its edges by 20%. The opposite picture is observed when internal air pressure decreases. Reducing tire pressure by 30% increases tire wear by 20%. In this case, tread wear in the middle of the treadmill is reduced by 15% relative to its edges. Uneven and, in particular, stepwise tire wear accelerates the wear of parts and assemblies of the entire vehicle.

Tire overloads are mainly caused by loading a vehicle with a mass exceeding its carrying capacity and uneven distribution of cargo in the vehicle body.

The nature of tire damage under increased load corresponds to damage when operating a tire with reduced internal air pressure, but wear and damage increase to a greater extent. The normal deflection, the contact area of the tire, the value and nature of the stress distribution in the contact area, and, consequently, the intensity of tread wear depend on the normal load.

As a result of overloading the frame, the side walls of the tires are destroyed, and breaks appear in the shape of a straight line. Overloading tires also causes additional fuel consumption and loss of vehicle engine power to overcome the rolling resistance of the wheels.

Signs of tire overload: sudden vibrations of the body when the car is moving, increased deformation of the side walls of the tires, somewhat difficult driving.

Some drivers believe that to reduce the effect of tire overload, they should be slightly inflated. This opinion is wrong. Increasing internal air pressure standards in combination with overloading reduces tire life.

When the vehicle is overloaded, the tires are deformed to a greater extent, and at the same time, the resultant of all forces applied to the section of the bead ring from the tire side moves closer to its outer edge. This contributes to increased deformation of the bead ring and its inversion, which can lead to spontaneous dismounting of the wheel while driving.

3.3. Incompetent driving

Inept or careless driving of a car, which causes premature wear of tires, manifests itself mainly in sharp braking up to the point of skidding and starting with a slip, in hitting obstacles encountered on the roads, in pressing against a curb stone when approaching sidewalks, etc.

When braking sharply, the ridges of the tire tread pattern slip on the road, which increases tread wear. The friction of the tire tread on the road when driving on fully braked car wheels, i.e. skidding, increases sharply, which increases the heating of the tread and destroys it faster. The higher the speed at which braking begins, and the more abruptly it is performed, the more the tires wear out. On a road with asphalt concrete pavement, this leaves a clearly visible mark consisting of small particles of tread rubber.

With prolonged skidding braking, first, increased local wear of the tire tread occurs in “spots”, and then the breaker and carcass begin to collapse. Frequent and sudden braking leads to increased wear of the tread around the circumference of the wheel and rapid destruction of the frame. In addition to severe tread wear, sudden braking creates increased tension in the threads of the carcass and bead of the tire. During sharp braking, large forces arise, which sometimes lead to the tread being torn off from the carcass. When you start abruptly and the wheels slip, the tread wears out in the same way as when you brake hard.

When driving inattentively, tires are often damaged by various metal objects found on the roads. Careless approach to the sidewalk, driving over protruding railway or tram tracks can cause the tire to become pinched between the rim and an obstacle, resulting in possible ruptures of the side walls of the tire frame, sudden abrasion of the sidewalls and other damage.

When a car moves around a turn, a centrifugal force occurs, applied perpendicular to the plane of rotation of the wheels. In this case, the side walls, bead and tread of the tire experience large additional stresses. On sharp turns and at increased speeds, the reaction of the road, counteracting the centrifugal force, is especially strong and tends to tear the tire off the wheel rim and tear the tread from the frame. This reaction increases tread wear.

As a result of careless driving, stones and other objects can get stuck between the dual tires, which crash into the sidewalls of the tires, destroying the rubber and tire frame.

At high vehicle speeds and, therefore, severe deformation, the dynamic load on the tire increases, i.e. Friction on the road, impact load, material deformation increase and the temperature in the tire rises sharply, especially at elevated ambient temperatures.

High driving speeds can lead not only to increased tread abrasion, but also to a weakening of the bond between the layers of rubber and fabric of the tire with possible delamination, and to patches falling off in the repaired areas of the tire and tube.

3.4. Irregular tire maintenance and repair

Unsystematic maintenance and untimely repairs are the main causes of premature failure and wear of tires. Failure to carry out the established amount of tire maintenance at the daily, first and second vehicle maintenance stations leads to the fact that foreign objects (nails, sharp stones, pieces of glass and metal) stuck outside in the tread are not detected in a timely manner and are not removed, which is why they penetrate deep into the tread , then into the frame and contribute to their gradual destruction.

Minor mechanical damage to the tire - cuts, abrasions on the tread or sidewalls, and even more so minor cuts, punctures, breaks in the frame, if they are not repaired in a timely manner, lead to severe damage that requires an increased volume of repairs. This is explained by the fact that when the tire rolls along the road, dust, grains of sand, pebbles and other small particles are filled into small cuts, punctures and tears in the rubber and frame fabric, as well as moisture and petroleum products. When a rolling tire deforms, grains of sand and pebbles begin to quickly grind the rubber and fabric of the tire, increasing the size of the damage. Moisture reduces the strength of the carcass cord threads and causes their destruction, and petroleum products cause the destruction of rubber.

The high temperature of the tire during rolling further accelerates the process of destruction of the tire material in places where it is damaged. As a result, a small hole from a cut or puncture gradually grows, causing the tread or sidewall to peel off. A partial rupture of the frame turns into a through one and leads to delamination of the frame and damage to the camera. Small mechanical damage, if not repaired in a timely manner, can cause, as it increases, an unexpected rupture of the tire along the way and cause a traffic accident. Untimely repair of large mechanical and other damage further increases the amount of repairs and contributes to the destruction of tires.

A particularly serious cause of premature failure of new and retreaded tires is their untimely removal from the vehicle for the first and second retreading, respectively. If the tire has not undergone retreading, then its service life has not been fully utilized.

Working on new or retreaded tires with a remaining tread groove depth in the center of the tread of at least 1 mm for passenger cars and buses, and even more so on tires with a completely worn-out pattern, in addition to a sharp reduction in the coefficient of adhesion of the tire to the road and, consequently, traffic safety cars, creates favorable conditions for further intensive destruction of the breaker and frame (breakdowns and ruptures). In such cases, due to a decrease in the overall thickness of the tread, a decrease in its shock-absorbing and protective properties, the tendency of the frame in the treadmill area to punctures and ruptures from impact concentrated forces acting on the tires when rolling on the road increases.

According to NIISHP, punctures and carcass ruptures occur in tires with a tread pattern that is worn out mainly by 80...90%.

The presence of punctures and carcass ruptures on tires reduces the service life of new and retreaded tires, making them often unsuitable for delivery for the first and repeated retreading, respectively.

The average mileage of retreaded tires of class 2 (with through damage) is approximately 22% lower than the average mileage of retreaded tires of class 1 by approximately 22% (NIISHP data). If you allow a tire to operate with an exposed breaker or carcass on the running surface, the tire quickly becomes unusable, since the carcass threads wear out greatly when rubbing against the road.

The exposure of threads in other places of the tire causes rapid destruction of the carcass fabric under the influence of moisture, mechanical damage and other reasons.

Working with cuffs applied to the through damaged area on the inside of the tire without vulcanization is only allowed temporarily as an emergency measure on the road or for tires that are beyond repair. Operating a tire with a cuff inserted into it leads to increased damage and gradual rubbing of the carcass threads by the cuff.

Working on tires with tubes repaired without vulcanization will cause the patches to quickly fall off.

3.5. Violation of the rules for dismantling and mounting tires

Vehicle operation shows that damage to 10...15% of tire beads, 10...20% of tubes and damage to wheels occurs as a result of improper removal and installation of tires. The reasons that contribute to the reduction in the service life of tires and wheels during installation and dismantling are: incompleteness of tires and wheels in size, installation of tires on rusty and damaged rims, non-compliance with rules and work methods when performing installation and dismantling operations; use of faulty and non-standard installation tools, failure to maintain cleanliness.

With increased dimensions of the chamber, folds form on its surface and rubbing of the walls during operation, and with reduced dimensions, the chamber walls stretch significantly and are more susceptible to rupture due to punctures and overload. The reduced size of the rim tape causes part of the rim to be exposed, and the tube is exposed to the harmful effects of rim corrosion products. In addition, the edges of the rim tape are destroyed and the chamber is squeezed out in the area of the valve hole, as a result of which its walls are also destroyed. The use of rim tapes with a larger diameter compared to the tire's mounting diameter entails the formation of folds, which during operation of the wheel chafe the tube. If the tire does not match the wheel dimensions, it will be damaged, resulting in a shorter service life.

A significant number of damage to the beads of tires occurs when mounted on dirty, rusty and faulty rims. The complexity of installation and dismantling largely depends on the condition of the wheels: the quality of the paint, the degree of corrosion of the contacting surfaces, the condition of the fastening parts, as well as the degree of “sticking” of the seating surfaces to the tire beads. Damaged rims cause chafing and various damage to the tire beads. Irregularities, scuffs and burrs on deep rims lead to tears and cuts in the tubes.

Incorrect techniques during dismantling and installation work lead to significant effort and mechanical damage to tire and wheel parts.

The use of faulty or non-standard mounting tools when mounting and dismantling tires often causes cuts and ruptures of the beads and sealing layer of tires, tubes and rim tapes, mechanical damage to the flanges, rim flanges and wheel disks.

One of the reasons for reducing the service life of tires is failure to maintain cleanliness during installation and dismantling work. Sand, dirt, and small objects getting inside the tires lead to destruction of the tubes and damage to individual cord threads of the inner layer of the tire carcass as a result of increased friction of the contacting surfaces.

3.6. Wheel imbalance

When the wheel rotates at high speed, the presence of even a slight imbalance causes a pronounced dynamic imbalance of the wheel relative to its axis. In this case, vibration and runout of the wheel appear in the radial or lateral directions. The imbalance of the front wheels of passenger cars has a particularly harmful effect, worsening the vehicle's handling.

Phenomena caused by imbalance increase wear on tires, as well as on vehicle chassis parts, deteriorate ride comfort, and increase noise when driving. The presence of an imbalance creates a periodic shock load acting on the tire as the wheel rolls along the road, which causes overstressing of the tire frame and increases tread wear. A large imbalance is created in tires after repairing local damage with the application of cuffs or plasters. According to NIIAT, the mileage of unbalanced repaired passenger car tires is reduced by approximately 25% compared to the mileage of balanced repaired tires. The harmful effects of wheel imbalance increase with vehicle speed, load, air temperature and worsening road conditions.

Depending on the location and function of the wheels (right, left, front, rear, drive and driven), tires have unequal loads and therefore wear unevenly. The convex profile of the road causes overload on the right wheels of the vehicle, which creates corresponding uneven tire wear.

Traction increases the load and wear on the tires on the driving wheels of the vehicle compared to the tires on the driven wheels. If you do not rearrange the wheels on a car, then uneven wear of the tire tread pattern can average 16...18%. However, frequent rotation of wheels (at each vehicle maintenance) can lead to an increase in specific wear of the tire tread by 17...25% compared to just a one-time rotation.

Foreign literature notes a significant effect of tire pre-running on wear. If new tires at the beginning of their operation (in the first 1000...1500 km) are given a lower load (50...75%) and then gradually increase it, then the total mileage of tires run in in this way increases by 10...15% .

A significant reason for premature tire wear is their use for purposes other than their intended purpose. Thus, tires with an all-terrain tread pattern, when used mainly on paved roads, wear out prematurely as a result of increased pressure on the road. In addition, the all-terrain tread pattern has reduced grip on hard surfaces, which leads to tire slipping on wet and icy surfaces and can cause the vehicle to skid and crash.

3.7. Malfunctions of the vehicle's chassis and steering

The most common cause of rapid wear of car tires can be incorrect alignment of the front wheels. Incorrect wheel alignment and camber cause increased tire wear due to additional slipping of the front wheel tire tread elements at the point of contact with the road.

If the camber of the front wheels deviates from the norm, one-sided increased wear of the tread occurs, and if the normal alignment is violated, increased wear of the edges of the tread occurs. The reason for one-sided wear with incorrect wheel camber is the concentration of the highest pressure in the outermost zone of the tread. Increased wear on the edges of the tread when the toe deviates from the norm is a consequence of the fact that the direction of rotation of the wheel does not coincide in this case with the direction of movement of the car. In this regard, the slippage of the tread edges periodically increases significantly.

Rapid local wear of the tread is caused by excessive wear on the vehicle's brake drum. The resulting ovality of the drum usually causes uneven braking of the wheel, as a result of which the tread wears out intensively only in certain areas around the circumference.

Overheating of the brake drums when the brakes are applied causes additional heating of the tires. If the brakes are adjusted incorrectly or their drive is faulty, excessive braking may occur, causing the wheels to skid. At the same time, tire tread wear increases significantly. The maximum braking force does not occur during full sliding, i.e. wheel skidding, and when rolling, there is some slippage. According to experimental data, the maximum braking force of tires on an asphalt concrete surface is obtained at 20...25% wheel slip.

According to numerous data, it is known that the tires of the driving wheels wear out more than the tires of the wheels not loaded with traction force (usually the front ones). In addition, the nature of wear on the front and rear, right and left wheels of a car is different, since they operate under different conditions. In this regard, to ensure uniform wear of the tires and increase the depreciation mileage, periodic rearrangement of the wheels is carried out.

Large play in the steering and bent parts of the steering rods, weakening of the springs and the presence of sharply protruding parts of the springs and body, deflection or misalignment of the front axle, oil leaks, sagging of the wings due to breakage or deflection of the brackets, non-parallelism of the axles - all this leads to increased wear or mechanical damage to the tread and side walls of the tire.

Worn or loose front wheel bearings and axle bushings, bent tie rods, or misaligned steering cause uneven, patchy tread wear. Bent or skewed (not parallel) axles cause excessive wear on the tire tread. Weakening of the spring contributes to subsidence and friction of the body on the tread with mechanical damage to it. Insufficient tightening of the nuts securing the wheel rims to the vehicle hubs results in “wobbling” of the wheels and, as a consequence, increased uneven wear of the tires.

When oil leaks through the axle seals from the rear axle housing, the tires are exposed to oil, which destroys the rubber.

4.1. Correct selection and equipping of vehicles with tires

Tires, depending on operating conditions, must have certain performance qualities. To operate vehicles in difficult road conditions and off-road, tires with high cross-country ability and reliability are desirable. In the southern regions, as well as in the middle zone, it is necessary to use tires with high heat resistance, and in the northern regions - with high frost resistance.

The rational choice of tires for cars means the choice of types, sizes and models of tires that would have the highest combination of qualities under specific operating conditions. The selection of tires by size, model, standard of unctuousness (load capacity index), type of tread pattern and their coordination with each specific model of car produced by the automotive industry is carried out in accordance with OST 38.03.214-80 "Procedure for coordinating the use of tires from the range produced by the tire industry industry."

When choosing tires, the type of construction is determined. For normal road and climatic operating conditions, tires of conventional designs are chosen - tubed or tubeless, diagonal or radial in mass production. Depending on the predominance of certain types of road surfaces, the tread pattern of conventional tires is selected.

To operate vehicles on paved roads, tires with a road tread pattern are chosen. For work on dirt roads and paved roads, tires with a universal tread pattern are used in approximately equal proportions. When operating in difficult road conditions, choose tires with an all-terrain tread pattern.

When choosing tires, take into account their overall dimensions, load capacity and permissible speeds, which are determined according to the technical characteristics of the tires.

The load capacity of a tire is assessed by the maximum permissible load on it. The load capacity criterion is the main condition for the correct choice of tire size, ensuring their operation without overload. To determine the required tire size, first find out the largest load (in kgf) on a car wheel, and then, according to the state standard or technical specifications, select the tire size so that the maximum permissible load on the tire is equal to or exceeds the permissible load by 10...20%. on a car wheel. Choosing tires with a certain reserve of permissible load ensures greater durability in operation. Along with the load on the wheel, when choosing a tire size, the vehicle speeds are taken into account, which should not exceed the permissible speeds for the tires.

Tires (including spare) of the same size, model, design (radial, diagonal, tube, tubeless, etc.) with the same tread pattern are installed on the car.

When partially replacing tires that have failed, it is recommended to equip the vehicle with tires of the same size and model as on this vehicle, since tires of the same size, but different models, may be of different designs, have different tread patterns, rolling radii , grip qualities and other performance characteristics.

The use of imported tires and their installation on cars of individual owners must take into account the operating modes of the cars.

Tires retreaded to class 1 can be used without restrictions on all axles of passenger cars. The retread class is determined in accordance with the tire operating rules (see Table 5.2).

To ensure traffic safety, it is not recommended to install tires with repaired local damage on the wheels of the front axles of cars. To improve the grip properties of tires and increase vehicle safety on snowy and icy roads, tires with anti-skid studs can be used. Recommendations for studding tires when operating rolling stock of motor vehicles using studded tires are set out in the Instructions for the use of anti-skid studs, published in 1974. Tires with anti-skid studs are installed on all wheels of the vehicle.

Rearranging studded tires for technical reasons is carried out without changing the direction of rotation of the wheels.

Cars intended for operation in areas of the Far North and equivalent areas (at temperatures below minus 45 ° C) should be equipped with tires marked “North”, i.e. in the northern version.

When operating vehicles mainly on soft soils and off-road, they must be equipped with tires with an all-terrain tread pattern. Long-term use of these tires on paved roads is not recommended.

Prohibited: installation on one axle simultaneously of diagonal and radial tires, as well as tires with different tread patterns; installation of tires retreaded to class 2 on the front axles of passenger cars.

Tires installed on the car are assigned to it, which is recorded in the tire operation cards and confirmed by the driver’s signature. The transfer of tires from one vehicle to another is carried out only with the permission of the technical manager of the ATP with a corresponding entry in the tire operation record card.

4.2. Rational vehicle driving mode

One of the factors that significantly influences tread wear, and therefore the tire service life, is the vehicle's driving mode. The main characteristic of the vehicle movement mode is the speed of movement, realized in specific conditions and time.

A gentle driving mode occurs during country trips on good roads and in good climatic conditions, with a small number of delays and low vehicle traffic intensity. It is tense in large populated areas with a large number of intersections, delays, restrictions and, therefore, braking, starting and acceleration, as well as in rural areas with bad roads.

The speed of a car is influenced by many factors, which can be conveniently presented in the following categories in the following order: driver, road and environment.

Car drivers directly control the movement of vehicles and the reliability and safety of traffic mainly depend on them. Driving a car is associated with great nervous and physical stress due to constantly changing road conditions, traffic intensity, the presence of intersections, traffic lights, etc.

The difference in the qualifications of drivers, in their ability to perceive and evaluate traffic conditions, is partially compensated by the choice by each of them of an acceptable speed of movement. A car driven by an experienced driver moves smoothly, evenly and at a fairly high speed, ensuring fast delivery of goods and passengers and relatively little tire wear. Inept and careless driving of a car often causes premature wear of tires and manifests itself mainly in sudden braking and starting; hitting obstacles on the roads or carelessly crossing them. Research has shown that when operating the same type of vehicle on the same route, the difference in tire mileage was 40...50%. Such a large difference in tire mileage is explained by the qualifications of drivers. These studies confirm the dependence of tire mileage on the experience of the driver and his ability to properly drive the car, choosing appropriate speeds in accordance with road and other conditions.

The speed of a particular vehicle depends significantly on the type and condition of the road. In urban environments, it additionally depends on traffic intensity, methods and means of traffic control, the number of intersections and situations at them, as well as other traffic obstacles characteristic of cities. The introduction of various coordinated movement methods that make it more likely to negotiate signalized intersections when traffic lights turn green without stopping increases both driving speed and tire mileage. Experienced drivers, as a rule, do not increase the speed before intersections, but, on the contrary, reduce it in order to avoid sudden braking and move off smoothly when the traffic light signal permits. This not only results in increased tire mileage, but also significant fuel savings. Imagine that there is a chicken egg under the fuel control pedal and by gently pressing the pedal you must move it, but not crush it. When the longitudinal profile of the road changes on slopes, if this is not related to traffic safety, it is advisable to coast. Coasting, when neither torque nor braking torques act on the wheels, allows you to reduce tire slippage in the contact patch with the road and increase its mileage.

On turns in the absence of bends (single-slope transverse profile), the speed of the vehicle must be reduced. On gravel and especially crushed stone surfaces, even when the road surface is treated with binding materials, as a result of abrasive wear, tire mileage is significantly reduced. To reduce wear on such roads, driving speeds should be lower compared to speeds on roads with asphalt, cement concrete surfaces and dirt roads.

The environment (geographical location, climate, season, weather) has a significant impact on tire mileage. Thus, in winter, the speed of cars and the ambient temperature are lower than in summer, i.e. There is less wear and therefore longer tire mileage. During the spring and autumn thaw, dirt roads become either difficult to drive or impassable at all. In these cases, as a result of frequent slipping, tire mileage is reduced.

4.3. Compliance with the rules for mounting and dismantling tires

Mounting and dismantling work on tires must be carried out in a tire service department using special equipment, devices and tools.

Only serviceable, clean, dry tires, tubes, rim strips, rims and their elements that match the size and type are subject to installation. Tires, tubes and rim tapes stored at temperatures below zero must be kept at room temperature for 3...4 hours before installation. Before installation, tires are inspected inside and out using a bead expander or other devices. Cameras are tested for leaks in water tanks. The tightness of valves with screwed-in spools is checked with soapy water, which is applied to the valve opening. New tires must be equipped with new tubes and rim strips. The same is recommended for tires retreaded using the retread method.

Rims and their elements are not allowed for installation if deformation, cracks, sharp edges and burrs, rust at points of contact with the tire, or developed mounting holes are found on them. The surface of the rims facing the tire must be cleaned of rust and painted with metal varnish. It is recommended to check new rims for axial (face) and radial runout. For passenger cars, the axial and radial runout of the rim and disc assembly in sections of the profile adjacent to the tire should not exceed 1.2 mm.

At each tire maintenance, as well as after each tire dismantling, it is necessary to balance the wheels.
This is done by removing the wheels from the car or directly on the car using stationary or mobile balancing machines in a service station.
When performing installation and dismantling work on tires, it is necessary to comply with the safety rules provided for in the technological maps for tire installation work and maintenance of automobile tires.
It is prohibited to dismantle tires in which the air pressure is higher than atmospheric pressure; the use of sledgehammers and similar objects during installation and dismantling work that can deform wheel parts.
Before mounting the tire on the rim, it is necessary to powder it with talcum powder on the inside and the inner tube on the outside.
To protect the spools from contamination and damage, all valves must be equipped with metal or rubber caps.
Installation and dismantling work on the way is carried out with the tool available in the installed driver’s kit.
It is prohibited to replace spool valves of various types with plugs.
To protect the tubes from damage, it is necessary to prevent sand and dirt from getting inside the tire.

4.4. Tire Maintenance and Storage

Tire maintenance is performed at each vehicle's TO-1 and TO-2 using special equipment. During maintenance of a car, work on tires and rims is performed simultaneously. This work includes the following: inspection of tires to determine their suitability for further use; elimination of stuck foreign objects in the tread, sidewall; sending tires with mechanical damage for repair; checking the serviceability of valves, spool valves, and the presence of caps; determining the suitability of tires based on tread wear and selecting them according to the vehicle axles; inspection of the rims to determine their continued suitability for use; checking the fastening of wheels and their elements; measuring the internal pressure in completely cooled tires with a hand-held pressure gauge, the readings of which are checked with the readings of the control pressure gauge; elimination of detected deficiencies in tires and rims.

During TO-2 of the car, work is simultaneously carried out on tires and rims in the scope of TO-1 and, in addition, the toe-in and camber of the wheels are checked, for example, according to the data indicated in Table 4, and their balancing. It is recommended to rearrange wheels on the same axle and along the axles of the vehicle when a technical need for this is identified, which is determined by the technical director of the automobile enterprise. The basis for tire rotation may be: identified uneven or intense wear of the tread pattern; the need to select tires by axle; the need to install more reliable tires on the front axle. If intensive or uneven wear of the tread pattern is detected, the reasons for its appearance should be determined and measures should be immediately taken to eliminate these reasons, regardless of the timing of vehicle maintenance. At the same time, the possibility of further use of these tires is determined.

To prevent premature failure of tires and ensure traffic safety during the period between TO-1 and TO-2 of the vehicle, the condition of the tires and wheels is monitored by the driver, as well as the checkpoint mechanic. It is prohibited to release vehicles onto the line if the following is found: the vehicle is equipped with tires of non-recommended sizes and designs; one axle of the car is equipped with diagonal and radial tires, as well as tires with different types of tread patterns; the air pressure in the tires does not meet the established standards or it is impossible to measure the pressure due to the presence of plugs or a faulty valve; the tread has wear more than the maximum permissible; there is unrepaired local damage to the tires (punctures, cuts, through and non-through, local tread delamination); foreign objects stuck in the sidewall of the tread were identified; there are no caps on the tire valves; The passenger car is equipped with tubeless radial tires with applied decorative sidewalls. If any deficiencies are found in the tires, the car is returned to its place to take measures to eliminate them.

Tires with extreme tread wear are removed and sent for restoration. The maximum wear of the tread pattern is considered to be such wear when the residual height of the tread pattern protrusions has a minimum permissible value over an area whose width is equal to half the width of the tread running track, and the length is equal to 1/6 of the tire circumference in the middle of the tread running track or with uneven wear over the area the same size. The minimum permissible residual tread height at which a passenger car tire must be removed from service is 1.6 mm. The remaining tread height is measured in areas of greatest wear.

At least once a week, it is necessary to check the internal pressure in all tires on vehicles entering the line. The internal air pressure in the tires must comply with the standards given in the operating instructions. When preparing cars for the transition to winter or summer operation, a full scope of work is carried out according to TO-2. Particular attention is paid to the correct selection of tires on the axles, to the timely removal of tires for repair, restoration and write-off.

At motor transport enterprises, in order to ensure the fullest use of tire life, it is necessary to ensure storage, packaging, installation and dismantling work in accordance with the rules for the operation of automobile tires.

Parking areas must be cleared of dirt; contamination of the parking lot with petroleum products, chemicals and other substances that destroy rubber is not allowed. The possibility of tires freezing to the ground due to the accumulation of water near them must be excluded. When using covered parking areas, cars should not be closer than 1 m from the heating system. Parking of cars in one place with a full load is allowed for no more than 2 days, unloaded - no more than 10 days. If you need to park your car for a longer period of time, you should unload the tires using stands or move the car.

Parking cars on tires with adjustable pressure in a loaded state under normal internal pressure in the tires without hanging the wheels on stands is allowed for 3 months, the internal pressure in the tires is checked every 4...5 days. It is prohibited to park vehicles on tires whose internal pressure is below the established standard.

To maximize the use of tires, the driver must strictly follow the rules for operating and caring for tires and monitor the internal air pressure in the tires. When receiving a new car, a complete or partial change of tires on a car, the driver is obliged to: check the tires installed on the car, including the spare one or those received for replacement; when partially replacing tires, select them according to the axles; Check the tire pressure and, if necessary, adjust it to normal. When installing a spare tire on a running wheel, it is necessary to check its compliance with the tires on this axle, record the speedometer readings to record the mileage of the spare tire, and, if necessary, bring the pressure in the spare tire to normal.

At least once a month, it is necessary to compare the readings of a manual pressure gauge with the readings of a stationary pressure gauge.

Before leaving the line, the driver is obliged to: inspect the tires to check their technical condition; check the air pressure in the tires (if air leaks from the tire, bring the pressure to normal); check the fastening of the rims and wheels. At least once a week, he should check the internal pressure in the tires with a manual pressure gauge.

On the line, the driver is obliged to: move the car smoothly to avoid wheel slip; when pulling the car to the side, immediately stop it and check the air pressure in the tires (it is prohibited to drive with reduced air pressure in constant-pressure tires even for a short distance, as this leads to the destruction of the tires, but a short-term decrease in air pressure in tires with adjustable pressure is allowed difficult sections of the route); monitor the condition of the road, reduce speed in difficult places; Avoid sudden braking when approaching a stop near traffic lights and barriers; avoid sharp impacts of wheels on sharp metal protruding objects; do not drive close to the edge of the sidewalk or other objects, so as not to damage the sidewall, tread and carcass of the tire; prevent prolonged wheel slipping when the vehicle is stuck; inspect tires in parking lots to determine the possibility of their further use; if there is an obvious air leak from the tire, measure the pressure and, if necessary, bring it to normal; do not allow the vehicle to be overloaded in excess of the established carrying capacity.

Every day after returning from the line, the driver is obliged to: inspect the tires, rims, valves, remove foreign objects from the tread and sidewall; remove tires that are subject to repair, restoration, scrapping due to mechanical damage, or extreme tread wear; If the tread wears unevenly, find out and eliminate the cause of its occurrence.

When operating radial tires, it is necessary to take into account their design features. Radial tires, compared to diagonal tires, have more elastic side walls, as a result of which, even with the increased pressure set for them, they have a radial deformation that is 10...15% greater than that of diagonal tires.

Driving with slightly lower than normal pressure in radial tires worsens the stability and controllability of the vehicle and leads to accelerated destruction of the sidewalls, frame and beads of the tires.

If the car is equipped with studded tires, the driver must first run them in for a mileage of 0.8-1.0 thousand km. When running in studded tires, it is necessary to avoid sudden starting and sudden braking. The driving speed during the running-in period should not exceed 70 km/h for passenger cars. When operating vehicles with studded tires on any road, it is not recommended to exceed speeds of more than 110 km/h.

The techniques for driving a car on studded tires in icy conditions are the same as using regular tires on a wet road in the summer. The braking distance of a car on studded tires in icy conditions is significantly reduced compared to the braking distance on non-studded tires in the same conditions, so the driver of this car needs to be especially careful when braking to avoid hitting a car behind.

If 10...15% of the studs fail to function, additional studding of the tires is allowed. After more than 50% of the studs fail, the remaining studs must be removed and the tires can be used in the summer until the maximum permissible wear of the tread pattern, after which they can be sent for restoration by applying a new tread.

When storing tires, fluctuations in air temperature and relative humidity are allowed within significant limits: temperatures from minus 30 to plus 35 ° C and relative humidity from 50 to 80%. Temperature and relative humidity in warehouses are controlled by ventilation of the premises.

New, retreaded, used but suitable for further use, as well as tires prepared for delivery for retreading, are stored in a vertical position on racks or on a flat floor.

Tires can be stored outdoors for up to 1 month in a vertical position under a canopy or covered with material that protects them from external influences.

During long-term storage, tires should be rotated, changing the support area every 3 months. The cameras are stored slightly inflated with air on brackets with semicircular surfaces. Tires, tubes and rim strips must not be stored in the same room as flammable, lubricant or chemical substances.

The appearance of electric cars on the roads has led to a lot of rumors, and one of them is that the car only travels 70-80 kilometers.

This is not entirely true, since the range of a Nissan electric car is influenced by a large number of factors, the main ones being driving style, the condition of the high-voltage battery and the outside ambient temperature.

What is economical driving

Economical driving not only helps you go further, but also extends the life of your Nissan Leaf electric vehicle.

firstly, economical driving extends the service life of the high-voltage part, since it is less subject to loads;
secondly, when you drive economically, use the brakes less and preserve their service life;
thirdly, an economical driving style is safer and, therefore, the risk of getting into an accident is reduced;

How to understand whether you are driving economically or not?! For a car with an internal combustion engine, the standard parameter is 1 liter of fuel per 100 kilometers. In an electric car, this is energy efficiency. It shows how many kilometers an electric car travels on one kilowatt-hour of energy.

An indicator of 7 kilometers per 1 kilowatt-hour of energy and above is considered economical, while consumption of up to 6 kilometers per 1 kilowatt-hour is considered optimal. If your consumption is lower, you should reconsider your driving style.

It is worth noting that in winter, consumption increases and with the heater on, the norm will be about 5 kilometers per 1 kilowatt-hour of energy.

You can see the consumption on the instrument panel, and to reset it you need to hold down the button on the panel on the left.

The most important principles in economical driving are smooth acceleration and speed. There is an indicator on the instrument panel that allows you to track how much energy is consumed during acceleration. It is depicted as white “balls” and these “balls” show the waste of energy. One “ball” is 8 kilowatt-hours, and the more you press the gas pedal, the more balls are displayed. On the left are green balls that show battery charge, that is, recuperation.

The most optimal overclocking option, in which you will spend a minimum of energy:

will accelerate on 2 balls up to 20 km/h;
after that, press the gas pedal a little harder and continue to move up to 50 km/h on 3 balls;
then release the accelerator pedal a little and continue driving on 2 balls;

Releasing the gas pedal for a few seconds and then pressing it again in an electric car has a detrimental effect on fuel consumption, since when you release the gas pedal, the car begins to brake with the engine and charge the battery. When you press, it spends this energy on acceleration and at this moment energy is wasted. Such a car spends more energy accelerating than it receives when braking. It is better to keep the gas pedal in one position while accelerating and release it only when you are about to come to a complete stop or significantly slow down.

Recovery

Recuperation is the conversion of a vehicle's kinetic energy into electrical energy. In simple terms, this is when the gas pedal is released and the car brakes with the engine, while at the same time charging the battery.

In this case, the electric motor works as a generator, and if you use recuperation correctly, you may not need to use the brake pedal. This technology, in addition to charging the battery, will also preserve the performance of the brake pads for a longer period, which in turn affects the list of work during scheduled maintenance.

Recuperation does not provide a global increase in mileage, but with the help of this technology, the car can travel 5-7% further.

It is best to use recuperation at moments of complete stop, releasing the gas pedal in advance so that the car can stop and collect as much energy as possible through recuperation.

In other cases, such as a long descent from a mountain, recuperation is not particularly effective.

Riding mode

Nissan Leaf has three driving modes:

DRIVE;
B (Break Recuperation);

With the “DRIVE” mode, the full power of the electric motor is available, the car has high responsiveness to the gas pedal, and recovery is insignificant.

Eco mode is the mode you should drive in to get the maximum distance. It creates a smoother response to the accelerator pedal, thereby reducing energy consumption during acceleration and enhancing recovery. In the Nissan Leaf manual, the manufacturer recommends driving in this mode.

Mode “B” is a mode of enhanced recovery. In it, the car is slowed down by the engine more than in Eco mode, but it is present only in the Nissan Leaf SV and SL trim levels until the 2015 model year; after 2015, all Nissan Leafs are equipped with “B” mode.

Mode “B” was developed more for driver convenience than for economy, so it is up to the driver to decide whether to use it or not.

Neutral gear

The next level in driving is to use neutral gear. Since the Nissan Leaf weighs almost 1.5 tons and has a low center of gravity due to the battery in the floor, it coasts well. This means that you can slide down small hills without wasting energy while maintaining speed, and if the hill is steeper, you can accelerate and, using recuperation, reduce the speed of the car to the initial speed, thereby recharging the battery.

To engage neutral gear, you need to move the gearbox joystick to the left and hold it for two seconds, after which the letter “N” will appear on the panel.

Climate system

The climate system in the Nissan Leaf is the biggest energy consumer after the electric motor, and its proper use will save a lot of mileage.

In the cold season, instead of a heater, try to use heated seats and steering wheel, as they consume significantly less energy, but if you have to connect a heater, then set the temperature to 18°C or 60°F (Fahrenheit), and the airflow intensity to 2 notches - this will be the most optimal option for using the stove.

In warm weather, try to limit the use of air conditioning. If you turned it on, then set the temperature to 24-25 degrees or 75-80 Fahrenheit, and leave the airflow at the same 2 levels.

Try to turn off the climate system 5-7 minutes before the electric vehicle comes to a complete stop or before a long stay of 20 minutes or more - this will help save some charge and will be the most optimal way to use the climate system.

Before the trip:

check tires to correct pressure;
preheat or cool the interior while charging the car from the mains cable;
remove unnecessary cargo from the vehicle;

While driving:

Drive in ECO mode - in the ECO position, a regenerative brake is applied when the accelerator pedal is released, compared to the D (drive) position, more energy is supplied to the lithium-ion battery;
ECO position helps reduce energy consumption by reducing acceleration compared to the same accelerator pedal position in D (Drive);
the ECO position reduces the power supplied to the heater and air conditioning system;

Drive at a constant speed. Maintain cruising speeds with constant throttle positions or using cruise control when necessary.

Accelerate slowly and smoothly. Gently press and release the accelerator pedal to accelerate and decelerate.

Drive at moderate speeds on the highway.

Avoid frequent stopping and braking. Maintain a safe distance behind other vehicles.

Turn off the air conditioner/heater when not needed.

Select a moderate temperature to heat or cool the interior to reduce energy consumption.

Use the air conditioning/heater with the windows closed to reduce drag when driving on the highway.

Vehicle range may be significantly reduced in extremely cold conditions (eg -20°C (-4°F).

Using the climate control system to heat the cabin when the outside temperature is lower (0°C) affects the vehicle's range more than using the heater when the temperature is higher (0°C).

Release the accelerator pedal to slow down and not apply the brake when traffic and road conditions permit.

The Nissan Leaf is equipped with a regenerative braking system. The main purpose of a regenerative braking system is to provide some power to recharge the Li-ion battery and extend the driving range. An additional benefit is “engine braking”, which operates under the conditions of lithium-ion batteries. In D (Drive), when the accelerator is released, the regenerative braking system provides some deceleration and some power to the lithium-ion battery.

The time that an electric bike battery can hold a charge is determined by many factors. These include: the mass of the rider, the speed and surface for riding, the frequency of acceleration and even the air temperature and the presence of wind. However, the main factors are motor power and battery capacity.

What is the significance of capacity?

Even before purchasing an electric vehicle, you should take into account the mileage declared by the manufacturer on battery charging, because this indicator, namely, the battery capacity, measured in V/h or Wh, is something that should not be neglected. This understanding is especially necessary when comparing different models. You can follow the rule: the higher the watt-hour rating, the better and the longer you can ride an electric bike without recharging.

How to reduce energy consumption?

Although it is unlikely that you will be able to increase the capacity of your battery, you can reduce energy consumption, thereby charging will last longer. This can be organized by properly using the capabilities of electric transport. Even if you have an electric bicycle, you should not neglect pedaling, because the principle of its use is based on the synergy of the motor and physical effort. By using the engine only when going uphill or when picking up speed, you will be able to drive much further. Owners of electric scooters are also advised not to forget to push off and coast.

How to care for the battery?

There are only a few rules for proper battery care, compliance with which also affects the performance and operating time of the battery.

Care instructions for regular use

If the charge level after the trip remains at 50-60%, it is necessary to recharge the battery without waiting for complete discharge, this is especially true for lithium options. You will be surprised how quickly your battery life will decrease if you forget to avoid completely discharging it.

If the indicator is almost zero, then it is better not to use electric vehicles at all and refrain from traveling until you can recharge, this will protect the battery from irreversible damage.

Please note that the voltage of lithium models is much higher when charged, which means that is when they deliver more power.

Storage rules

Be sure to discharge the battery to 50% before long-term storage of electric vehicles.
Check the charge level approximately every few months and periodically recharge the battery to the recommended 50%. This is especially true for lithium batteries - they absolutely cannot be stored completely discharged. Failure to comply with this rule may result in failure of the device, and malfunctions due to violations of storage conditions are not covered under warranty.
You cannot charge the battery in the cold. Only at above-zero temperatures!
The temperature in the room where the battery is stored should be within 20-25ᴼ.

Use in winter

Most models of lithium batteries can be used at temperatures up to -20ᴼ. However, in this case, the capacity of the device will decrease significantly (temporarily). In addition, it is better not to overload an insufficiently warmed battery with high power. After using an electric vehicle in the cold, it is better to wait a little while charging the battery until it warms up to room temperature.

Disposal

Those batteries that have served their service life must be recycled to special organizations. You cannot throw away the battery along with other household waste; this is an environmental crime, because such a battery can pollute tens of cubic meters of soil.

Do you want to increase sales of your products or services?

There are two news: good and bad.

The good news is that after reading this article you will learn 3 fundamental secrets to increasing sales.

The bad news is 90% of people won't use it these secrets. Not because they are worthless or difficult to implement. No. Just people in an eternal search for magic buttons, magic pills and universal life hacks.

100 tips for a sales manager
100 objections. Business and sales
111 ways to increase sales without increasing costs
Work with objections. 200 sales techniques for cold calling and personal meetings.

I'm not against books like this. Most of them may even be useful. BUT! They can only be useful as a supplement.

The sales system itself must be built on unshakable foundations. Like a house on a strong foundation.

In this article you will learn about how to increase sales by building a system that works:

In any market
In any conditions
For any product (product, service, education, software).

For simplicity, I will use the word “product” in the examples. By this I mean services, software, and educational products.

Secret No. 1. Low entrance fee

We can look at the relationship between seller and buyer through the lens relationships between ordinary people. For example, men and women.

Let's imagine that a young man comes up to a girl completely unfamiliar to him and says: "Will you marry me?".

At best, they will laugh at him. Why should a girl marry the first person she meets?

But most companies build sales this way. They immediately invite the person to go to very serious step: make a purchase for an impressive amount.

Someone might object:

"But the potential customer knows that they have a need. And they also know that our product can satisfy that need."

Let's return to the example of human relationships. Imagine that a young man approaches a girl and this time operates with the following:

“You don’t have a wedding ring on your hand. This means you are unmarried. You look 20-25 years old. At this age, 90% of girls want to get married. So, maybe you don’t mind if you and I get married?”

Just because a guy knows about a girl’s desire does not mean that she will want to marry him. And even if he wants to, it’s definitely not at the first meeting.

The presence of a product does not mean that a potential client will want to buy it from you. And even if he wants to, it’s unlikely at the first meeting.

But how do ordinary human relationships work?

Usually a guy invites a girl for a cup of coffee. A cup of coffee is absolutely small commitment which is easy to agree to (unlike marriage).

If everything goes smoothly at the first meeting, then the guy can invite the girl to lunch, dinner, and so on.

The easiest way to increase sales for your company will be if in the first step you offer small micro-commitment. Having made this micro-commitment, the potential client will be satisfied and will look forward to further, more serious proposals from you.

The entrance ticket can be either paid or free.

A free entrance ticket can be any lead magnet – a piece of very useful information. For example, for an online cosmetics store, a good lead magnet would be the PDF brochure “5 Rules for caring for oily skin.”

After reading this brochure, a potential client:

Will receive value from you in the form of useful information
He will begin to trust you, because after reading the information from the lead magnet, he will be convinced of your competence
Finds out what skin care products he needs and where it is more profitable to buy them (from you).

A paid entry ticket can be a product sold at cost or even free (with delivery charges). For example:

With the admission ticket we get two very important benefits.

First of all, we convert as many people as possible from just “passers-by” to clients. Why is it important? Because it is much easier to sell to an existing client than to someone who sees us for the first time.

Secondly, with a small micro-commitment, we evoke two of the most important feelings in a potential client: trust and gratitude.

Many companies know the importance of trust. This is why they love to show reviews and cases.

But many people forget about gratitude. But this is a very powerful weapon...

Robert Cialdini

The first rule of influence is gratitude.

In simple words, people feel obligated to those who give them something. gave first.

If a friend invites you over, you will feel obligated to invite him back.

If a colleague does you a favor, you feel like you owe him a favor in return.

In the context of social relationships, people are more likely to say yes to those to whom they owe something.

The effect of the “Law of Gratitude” can be clearly seen in a series of experiments, spent in restaurants.

On your last visit to a restaurant, the waiter may have given you a small gift in the form of chewing gum, a mint, or a fortune cookie. This is usually done when the bill arrives.

So, will giving a mint affect how much you tip? Most will say no. But in fact, this small gift, like a mint candy can change everything.

According to research, giving one mint to a guest at the end of a meal increases the average tip 3%.

Interestingly, if you increase the size of the gift and give two mints instead of one, the tip does not double. They quadruples in size- up to 14%.

But perhaps the most interesting thing is that if the waiter gives only one piece of candy, he turns around and starts to leave, then pauses, comes back and says:

“But for you wonderful people, here’s an extra piece of candy,” then the tip just skyrockets.

Average, tips increase by 23% not due to the number of gifts, but due to the fact how they were handed over.

Therefore, to use the Law of Gratitude effectively, you must to be first, who gives...and make sure that the gift is personalized and unexpected.

As I said, using the Law of Gratitude can be a powerful weapon. For example, major drug trafficker Pablo Escobar used the “Law of Gratitude” for his own purposes.

He built houses and provided food for the poor people. In response, they undertook to protect him, carry out his instructions and were literally ready to die for him.

Request!

If you are selling something illegal, harmful, immoral or useless, please do not read further. I don't want to see good marketing used for bad purposes. Also, no amount of marketing will help if you have a bad product.

Simply implementing a cool entry ticket can double your sales. And you no longer need to look for 100,500 ways to increase sales.

What entry ticket can you use to increase sales of your business?

If you sell products it could be:

Lead magnet (a piece of valuable information: PDF report, price list, e-book)
Small free gift
Coupon
Discount
Sample

Here is an example of the discount that Godaddy provides for purchasing a domain (1st year):

We see that at first Godaddy gives away the domain 8 times cheaper (payment for the second year):

A huge discount is the entry ticket to this domain registrar.

TOak increase sales of services? Use the following entrance tickets:

Leadmagnet
Service at a very low price
Consultation

For example, on the website kwork.ru almost all services cost 500 rubles (a good entrance ticket):

If you sell software, The entrance ticket can be:

Trial period
Demo version
Product demonstration video
Consultation

For example, one of the most expensive email messaging services, ExpertSender, offers a live demonstration of the program as an entrance ticket:

They don’t even show rates on the website, but use a price list in the form of a lead magnet:

If you sell educational products, your ticket of entry might be:

I would like to point out that implementing an admission ticket increases your company's sales, but does not necessarily increase its income. Because income and sales often do not correlate with each other.

But how to increase the company's sales increase its profitability? Secret number 2 will help with this...

Secret No. 2. Expand your product line

Since you won't get rich by selling admission tickets, you need to offer other products to your customers. For example, when purchasing a domain, you will also be offered the option of protecting contact information:

professional mail:

and similar domains:

When purchasing a service on Kwork, you will also be offered additional options (urgent execution, additional edits):

Big companies like Apple, McDonalds, Amazon do the same thing...

Did you know that selling a burger for 2 dollars 9 cents McDonald's makes money only 18 cents? This is because every client costs this company V 1 dollar 91 cents:

$2.09 - $1.91 = $0.18

But how does McDonald's make money then?

On Coca-Cola and French fries. Together they bring $1.14 (profit growth 6.3 times). As you can see, a competent product line can increase profits significantly.

On the iHerb website, additional products are sold using the “Frequently purchased with this product” widget:

Want to know how increase product salesas quickly as possible? Just offer the customer related products when placing an order. You'll find that increasing product sales has never been easier.

Companies spend the most money on attracting customers. Therefore, every additional sale to existing customers, every additional option or product increases profits incredibly.

If we talk about methods increasing sales and profits– a large product line without competition. And developing it is not that difficult.

In your business you can:

Come up with a new product.
Make a premium version of an existing product.
Combine several products and make a set.
Create a subscription.

Easiest to implement premium version existing product and set of products.

For premium version you can add additional features, extended support, and so on.

Sets products are good because it is more profitable for the client to buy it than each product separately. For example, you have three products for $500. You create a set and sell it for $1000 (instead of $1500).

Subscription is one of the best monetization options since the client pays you on a regular basis. For example, if you have a car wash, you can launch a subscription: an unlimited number of car washes for 1,000 rubles per month.

There are companies that combine subscriptions and product bundles. For example, the streaming company DAZN has revolutionized the world of sports broadcasting.

If previously boxing fans had to pay a TV channel $65 to watch one interesting boxing evening (PPV), now they can pay the streaming service $10 a month and watch all sporting events for 30 days.

Total value of products from the last box is 8428 rubles. But you get it all for only 1400 rubles.

Why is the company taking this step? Behind what is now they have a guarantee what you will pay every month. You can also buy other products from them that are not included in the sets (Law of Gratitude).

If you're looking for creative ideas to increase sales, consider expanding your product line. Sets, subscriptions, passes, premium packages - there are more than enough options.

Secret No. 3. Return track

The reality is that not all potential clients will sign up for your entry ticket. Not everyone will buy the main and related products. Therefore, it is very important to have a return path.

Increasing company sales through a return track is one of the most underestimated opportunities.

The return path is clearly defined scenarios for the return of potential clients to purchase your products. If they have already purchased, we use the return track to encourage repeat purchases.

To implement a return track we can use:

People often ask whether promotions can be used to increase sales. Stocks are another tool return tracks. Use them wisely and you can significantly increase your sales.

Better yet, stop looking for different tricks to increase sales. If you want long term growth, use the basics which you have just learned about.

How to implement all this in your business? I prepared it especially for you premium video “One-page sales system”. After watching it, you will get a clear plan to increase sales in your business.