Construction of car tires
The tire consists of: carcass, breaker plies, tread, bead and side part.
Tire design: 1 - tread; 2 - shoulder part; 3 - frame; 4 - side part; 5 - breaker; 6 - additional insert in the shoulder area (green); 7 - side ring; 8 - side part
frame- the main power element of the tire, consists of rubberized cord threads. The cord can be textile, metal or fiberglass. Textiles and glass are used in passenger tires. Metal cord - in trucks. Fiberglass is absolutely resistant to decay and stretching. Tires using fiberglass wear out less and are less prone to deterioration in conditions of high humidity and temperature (tropics).
Breaker is located between the carcass and the tread (cushion). It is designed to protect the carcass from impacts, to stiffen the tire at the point of contact with the road surface and to protect the tube from punctures. It is made from a thick layer of rubber (in light tires) or crossed layers of steel cord.
Tread the outer rubber part of the tyre. Provides tire grip with the road, and also protects the carcass from damage. The tread has a certain pattern, which, depending on the purpose of the tire, varies.
Board allows the tire to seal tightly on the wheel rim. To do this, it has side rings and is coated on the inside with a layer of viscous airtight (for tubeless tires) rubber.
Side part protects the tire from lateral damage.
Anti-skid spikes. In order to improve the safety of the car in conditions of ice and icy snow, metal anti-skid spikes are used.
Distinctive features of tires
Pneumatic car tires differ in the method of sealing the internal volume, the location of the cord threads in the tire carcass, the height and width of the profile, the type of tread, and seasonal destination.
According to the method of sealing tires are chamber and tubeless. Tubeless tires are currently replacing tubeless tires.
Tube tires (TUBE TYPE)
Tube tires consist of a tire, a chamber with a valve and a rim tape worn on the rim of the disc. 
The design of the wheel with a tube tire: 1 - disc rim; 2 - camera; 3 - tire (tire); 4 - valve
The valve is a non-return valve that allows air to be forced into the tire and prevents it from escaping to the outside. 
Chamber valve: 1 - spool rod; 2 - threaded head; 3 - bushing; 4 - sealant; 5 - upper cup; 6 - spool sealing ring; 7 - lower cup; 8 – valve body; 9 - spool spring; 10 - guide cup; 11 - rubberized casing.
Rim tape protects the tube from damage and friction on the disc and rim of the tire.
Tubeless tires (TUBELESS)
Tubeless tires (TUBELESS) characterized by the presence of an airtight layer superimposed on the first layer of the frame (instead of the camera) 
The design of the wheel with a tubeless tire: 1 - tread; 2 - sealing airtight rubber layer; 3 - frame; 4 - wheel valve; 5 - rim.
Tubeless tires have a number of advantages over tubeless tires, which are expressed in the following:
- reduced weight and low moment of inertia;
- improved balancing;
- increased safety and reliability, due to the impossibility of rapid depressurization;
- minimal downtime on the road, which was reduced by an average of 60%, due to the ability to repair small tire punctures with a special paste (this does not require removing the tire from the wheel);
- increased mileage - an average of 11%. This is achieved due to the absence of friction between the chamber and the tire, stable internal pressure and optimal temperature, which is maintained due to the increased heat transfer from the tire to the rim.
Chambered and tubeless tires according to the location of the cord threads in the carcass can be either diagonal so radial designs. 
The design of the diagonal (a) and radial (b) tires: 1 - sides; 2 - bead wire; 3 - frame; 4 - breaker; 5 - sidewall; 6 - protector.
In radial tires, the cord threads are located along the radius of the wheel, and in diagonal tires, at an angle to the radius of the wheel, and the threads of adjacent layers intersect. Radial tires are more rigid, they have a longer resource, better contact patch shape stability, and lower rolling resistance.
Depending on the purpose and operating conditions, tires are divided into:
Road(commonly called summer), designed for use at positive temperatures on highways. Tires of this type provide the best grip on dry and wet roads, have maximum wear resistance and are best suited for high-speed driving. For driving on dirt roads (especially wet) and in winter, they are of little use.
Winter used on icy and snowy roads, the grip of which may vary depending on the situation, from minimal (smooth ice or porridge of snow and water) to small (packed snow in the cold). They have good road properties, somewhat inferior to the summer “rubber”. Many winter tires allow the installation of anti-skid studs or are already studded at the factory.
All season are a compromise between summer and winter tires, therefore they are inferior in terms of grip to both the first and second tires in the conditions appropriate for the season. They allow year-round operation of the car on one set of tires.
Universal have properties that allow them to be used both on highways and on dirt roads. It is advisable to use them for off-road vehicles that make approximately equal runs on highways and roads. It can be quite difficult to draw a clear line between them and all-season tires.
Cross-country ability designed for off-road and soft soils. It is desirable to use such tires only for occasional traffic on the highway. Otherwise, they will wear out faster and create a high level of noise.
Tires can also be classified according to the shape of the profile.
regular profile(82-70% of tire width, e.g. 165/ 70
R13)
Low profile(65-50% of tire width, e.g. 225/ 60
R17)
Ultra low profile (<50 % от ширины шины, например, 255/40
R18)
wide profile- are applied on cars of big loading capacity, all-wheel drive cars and trailers. Their use allows you to increase the cross-country ability of the car (on certain soils), reduce the consumption of materials, since they are often used on one tire, instead of dual
Arched- they are installed on the rear axle of trucks on one tire, instead of two conventional profiles. The arch tire tread has sparsely spaced lugs. The use of these tires dramatically increases the patency of cars on soft soils, sand, virgin snow, wetlands. Their use on paved roads is limited.
Basic tire marking parameters
Tire manufacturers label their products according to general requirements, so all the main characteristics can be seen on the sidewall of the tire.
Marking can be in metric, inch or mixed system. Our tires are marked mainly in the metric system.
An example of marking in the metric system:
225/75R16 104R
The first parameter can be the bus type.
Tire type - (Service Type)
P LT ST- (Special Trailer) trailer, T
225 /75R16 104R
Tire width - (section width)
tire profile width in millimeters from sidewall to sidewall.
225/75 R16 104R
Profile width to height ratio - (aspect ratio)
the percentage of the width of the tire profile to its width, in this example 75 means that "tire width" / "tire height" = 75%. If this designation is absent, then it is considered equal to 82%.
225/75R 16 104R
Tire construction [R] – (Internal Construction)
a designation that reflects the features of the construction of the tire cord. Possible values: R– (Radial) tire carcass of a radial type (a common mistake when the letter R is mistaken for a radius designation). In radial-type tires, the tire carcass cord is stretched from bead to bead and the rubberized threads do not overlap, but lie parallel to each other around the entire circumference of the tire and thereby form a carcass layer. D- (Diagonal) diagonal frame type. A feature of the construction of diagonal tires is that the cords are located at an angle to the radius of the wheel. In one layer, the threads go in one direction, in the other layer, in the opposite direction. As a result, the threads of adjacent layers intersect. B - (Bias belt) diagonal belted tire. The carcass of a tire of this design is similar to bias tires, but in such a tire there is still a breaker, like in radial tires. If this designation is absent, then this means that the tire has a diagonal carcass type.
225/75R16 104R
Tire diameter - (rim diameter)
tire diameter or mounting diameter of the tire. The distance in inches from one inner edge of the tire to the other is also equal to the diameter of the rim.
225/75R16 104R
Load index - (load index)
shows the maximum allowable load on one tire at optimal tire pressure, at the maximum allowable speed. In addition to this, the load may be indicated on the tire - Max load (in kg). Table for converting the load index to kilograms.
| Load index | 60 | 65 | 70 | 75 | 80 | 85 | 90 | 95 | 250 | 290 | 335 | 387 | 450 | 515 | 600 | 690 |
| Load index | 100 | 105 | 110 | 115 | 120 | 125 | 130 | 135 | 800 | 925 | 1060 | 1215 | 1400 | 1650 | 1900 | 2180 |
Duplication of the maximum load index (1984LBS or 900kg.) 
225/75R16 104R
Speed index [R] – (speed symbols)
shows the maximum allowable speed of the car on such tires at full load. The operation of tires at maximum permissible speeds and loads significantly reduces their resource. It is not recommended to use tires at 100% of the possible load and 100% of the permissible speed - this can lead to their destruction. Table for converting the speed index into numerical values.
| Speed index | A1 | A2 | A3 | A4 | A5 | A6 | A7 | A8 |
| Speed, km/h | 5 | 10 | 15 | 20 | 25 | 30 | 35 | 40 |
| Speed index | B | C | D | E | F | G | J | K |
| Speed, km/h | 50 | 60 | 65 | 70 | 80 | 90 | 100 | 110 |
| Speed index | K | L | M | N | P | Q | R | S |
| Speed, km/h | 110 | 120 | 130 | 140 | 150 | 160 | 170 | 180 |
| Speed index | T | H | V | W | Y | VR | ZR | ZR(Y) |
| Speed, km/h | 190 | 210 | 240 | 270 | 300 | >210 | >240 | >300 |
AT inch system dimensions are in inches.
For example bus parameters 35x12.50 R 15LT 113R are deciphered:
35 x12.50 R 15 LT 113R
External diameter tires in inches
35x12.50 R 15LT 113R
Tire width
– (section width)
tire width in inches. (Note that this is the width of the tire, not the tread. For example, for a tire with a specified width of 10.5 inches, the tread width will be 23 cm, not 26.5, and a tire with a specified width of 12.5 will have a tread of 26.5 cm.) If the outer diameter is not specified, then the profile is calculated as follows: if the tire width ends in zero (for example, 7.00 or 10.50), then the profile height is considered equal to 92%, if the tire width ends in a non-zero (for example, 7.05 or 10.55), then the profile height considered equal to 82%
35x12.50 R 15LT 113R
Tire construction [R] – (Internal Construction)
designation indicating that the carcass of the tire is of a radial type.
35x12.50 R 15LT 113R
Tire diameter - (rim diameter)
tire diameter or mounting diameter of the tire.
35x12.50 R 15LT 113R
Tire type - (Service Type)
optional designation (mandatory by DOT for North America), indicates the purpose of the tire. Possible values: P- (Passenger car designation) passenger car, LT- (Light Truck) light truck, ST- (Special Trailer) trailer, T- (Temporary) temporary, used only for spare tires.
35x12.50 R 15 LT 113 R
Load index - (load index)
shows the maximum allowable load on one tire at optimal tire pressure, at the maximum allowable speed.
35x12.50 R 15LT 113R
Speed index [R] – (speed symbols)
shows the maximum allowable speed of the car on such tires at full load.
For diagonal tires were labeled in a mixed system.
For example 8,40-15/215-15
Here
8,40
- tire width in inches
15
- disc diameter in inches
Through the fraction is the designation of the tire width in millimeters and the wheel diameter in inches
Additional tire marking options
Tire operating conditions
Winter- Winter tires.
Snowflake pictogram- tires are marked for operation in severe winter conditions.
Aqua, Rain, Water, Aquatred, Aquacontact, etc. (or umbrella icon)- indicates that the tires are effective on wet roads.
AS, All Season or A.G.T. (All Grip Traction)– designation of all-season tires
AW or Any weather– all-weather
M+S (Mud+Snow) or M&S– Mud and snow, winter or all-season tires are specially designed to improve vehicle handling when driving in mud or snow. At the end of the marking may be " E" - studded tires.
If the tire does not have the above symbols on the sidewall, then this tire is intended for use only in summer conditions.
All Terrain- designation for all-terrain tires with universal properties designed for off-road vehicles.
Max pressure- The maximum allowable pressure, measured in kPa.
Max load– The maximum allowable tire load, measured in kg (or English pounds).
ROTATION with direction arrow- applied to tires with a directional tread pattern, indicates the direction of rotation of the tire.
DOT- Compliance with US standards. The U.S. Department of Transportation requires tire manufacturers to conduct a tire quality assessment [Tyre Quality Classification], with the exception of winter tires. This code specifies the company and factory, soil, lot, and production date (2 digits for the week of the year plus 2 digits for the year; or 2 digits for the week of the year plus 1 digit for the year for tires made before 2000.)
E in a circle- tires are marked according to the requirements of ECE (Economic Commission for Europe). The number indicates the country of approval. 
Reinforced(or letters RF at the end of the size) - indicate that the tire is reinforced, used for vehicles with increased load capacity, and has 6 layers. Letter C in size, denotes a cargo tire having 8 plies.
XL (Extra Load)- Reinforced tyre.
Radial- a tire of a radial design. The same as the letter R in the standard size.
Steel (steel belted)- it means that in the design of the tire, there is a metal cord.
Outside, Side Facing Out- the outer side of the tire with an asymmetric tread pattern. During installation, the word Outside must be on the outside of the machine.
Inside, Side Facing Awards- the inner side of the tire with an asymmetric tread pattern. During installation, the inscription Inside must be on the inside of the machine.
Retread- restored;
Plies– tire design features – Tread area: – composition of the tread layer; Sidewall: - the composition of the sidewall layer. 
Tubeless or TL– marking of tubeless tires. The absence of this marking indicates that the use of this tire is only possible with a camera.
Tube Type, TT or MIT SCHLAUCH– The tire must only be operated with a tube.
Parameters reflecting the quality of tires, according to the American UTOG tire quality classification system:
Traction A, B or C- the coefficient of adhesion with the road surface or the ability of the tire to brake.
It takes the values A, B, C. Coefficient A means the highest clutch value in its class.
Temperature A, B or C- an indicator characterizing the heat resistance of the tire. Possible values are A, B and C. A is the best
Treadwear 200- wear resistance coefficient, determined in relation to the base tire (it has it equal to 100) of a particular manufacturer. It is obtained by conducting standard tests in the United States.
TWI (tread wear index) or TWID- indicates the location of the wear indicators of the projector, the protrusions at the bottom of the tread grooves. When the tread wears down to the level of these indicators, the tire is considered unsafe and it is time to replace it.
Date of manufacture of the tire (four digits enclosed in an oval or rounded rectangle)- the first two digits indicate the ordinal number of the week in the year, the next two indicate the year of manufacture.
DA (stamp)- indicates minor manufacturing defects that do not interfere with normal operation.
The tire also says:
Trademark, manufacturer's name
Trademark (tire model).
Made in ... - the name of the country of the tire manufacturer.
FB - (Flat Base)– marking of tires without wheel rim protection.
FR - (Flange protector)– marking of tires with disc rim protection.
Green X, Reduces CO2– tire designations with low rolling resistance, indicate fuel savings due to the use of such tires.
RunFlat, RunOnFlat, HP, SSR, SST– signs indicating that these are emergency running tires, make it possible to continue driving even when the wheel is lowered.
RPB (Rim Protection Bar) or MFS - (Maximum Flange Sheild)– protection of the disc rim from damage against curbs and sidewalks.
Colored labels used for tire marking:
Yellow marking on the tire(round or triangular mark) on the sidewall indicates the lightest spot on the tire. When installing a new tire on a rim, the yellow mark must be aligned with the heaviest spot on the rim. This is usually where the nipple is attached. This allows you to improve the balance of the wheel and put weights of less weight.
On tires with mileage, this yellow marking is not so relevant, since, as a rule, when the tire wears out, its balance shifts.
Red marking (red dot on the tire)- means the place of maximum power heterogeneity, the manifestation of which is usually associated with various connections of different layers of the tire during its manufacture. These irregularities are completely normal and all tires have them. But usually only those tires that go to the primary equipment of cars are marked with red dots, i.e. when the car leaves the factory.
This red mark is combined with white marks on the discs (white marking marks on the discs are also placed mainly for the original configuration of the car), which indicate the closest place to the center of the wheel. This is done so that the maximum inhomogeneity in the tire is minimally affected when driving, providing a more balanced power characteristic of the wheel. During normal tire fitting, it is not recommended to pay attention to the tire marking with a red mark, but to be guided by the yellow mark, combining it with the nipple.
Marking - white stamp with number means the number of the inspector who carried out the final inspection of the tire at the manufacturing plant
colored stripes on the tire tread are made to make it more convenient to "identify" the tire in the warehouse. All tire models and different sizes have different markings. Therefore, when tires are stacked in warehouses, it is immediately clear that a given stack of tires has the same size and model. These colored stripes on the tire have no other semantic load.
Often manufacturers indicate pictograms on tires:
A graphic symbol representing snowflake on a mountain background tires are marked for operation in severe winter conditions. This symbol was introduced by American and Canadian manufacturers. It is known by the acronym 3PMSF (Three Peak Mountain Snow Flake)
Pictograms on the universal (all-season) tire.
From left to right, this means: summer, rain, snow, fuel economy, confident cornering. Others, if they introduce similar badges, try to keep them on the company's website, because this information is needed only when choosing tires.
The requirements that the cord must meet are as follows:
high strength under repeated loads;
heat resistance and thermal conductivity;
excellent elasticity;
high density;
Uniformity in physical and mechanical properties;
high efficiency.
The use of fiberglass is justified by its resistance to stretching and rotting. Therefore, and having a fiberglass cord, have higher performance characteristics. Cord made of cotton fibers is currently not popular, as it has been replaced by cords made of polyamide fibers, viscose, and metal cord.
Cord fabric makes up approximately 28-30% of the total mass of the tire, but at the same time it experiences the maximum load during the operation of the tire and gives the latter wear resistance, strength and elasticity. The cord thread in the tire operates under conditions of tension, compression and multiple bends in a wide temperature range (from -50 to +110°C).
METALCORD
Currently, tires with steel cord have gained great popularity, which are produced in the following types:
· tires with metal cord in breaker and carcass;
Tires with metal cord of the sub-groove layer and nylon cord in the carcass;
· Tires with a metal cord in the breaker and a nylon or steel cord with a meridional arrangement of threads in the carcass.
The difference between tires with a metal cord from other samples is the presence of wider ones. Plus, in the zone (on the inside of the carcass) tires with steel cord have a vulcanized rubber layer. This allows, on the one hand, to achieve an even distribution of stress in the tread area, and, on the other hand, to protect the chamber from mechanical damage, in particular, from punctures.
Advantages of steel cord tires
Tires with steel cord have a number of advantages over other offers, including:
high strength, which makes it possible to produce tires for trucks with 2 to 4 layers of cord in the carcass instead of the traditional 8-14;
increase in tread thickness, which leads to a long service life, on average, such tires last twice as long as traditional ones;
Decreased sway
· high rates of heat resistance and thermal conductivity reduce stress, and also contribute to uniform temperature distribution.
But with all its advantages, the steel cord is characterized by low fatigue strength with repeated significant deformation.
VISCOSE CORDS
Viscose fabric cords are classified as textile materials, since artificial fibers are used for their manufacture, the material for which is cellulose. In terms of physical and chemical characteristics, viscose cord is superior to cotton cord and is characterized by:
greater uniformity of the thread;
improved resistance to deformation;
Higher strength with increasing temperature;
Reduced heat generation during tire operation.
Viscose cord tires have a higher mileage: up to 70% on average compared to cotton cord samples. With all its advantages, viscose cord also has disadvantages, which include susceptibility to moisture and a low coefficient of adhesion to rubber.
POLYAMIDE CORDS
Polyamide fibers, and in particular nylon, are the most suitable cord material. It has the following advantages:
high elasticity;
Great strength;
The lightness of the frame
almost complete recovery after tensile/compression loads;
low water absorption.
The strength of nylon cord exceeds cotton and viscose counterparts, plus it is not inferior in strength to steel cord, but exceeds it in fatigue strength.
Car tire- is an elastic rubber-metal-fabric shell installed on the wheel rim. The tire ensures the contact of the vehicle with the roadway, is designed to absorb minor vibrations caused by the imperfection of the road surface, to compensate for the error in the wheel trajectories, to implement and perceive the forces that arise in the contact patch.
winter tire- a tire for a car, designed specifically for use in the cold season at temperatures below +7 ° C.
The main differences between these tires are the specific properties of rubber and tread pattern. Rubber compounds are designed so that at low temperatures the tire retains its elasticity, which guarantees better grip and shorter braking distances on cold, wet, snowy and icy road surfaces. As for the tread pattern of a winter tire, it is distinguished by a high density of sipe cutting. All of the above features allow for better handling and efficient braking.
Tread(pr otect — protection) - an element of the tire (tire) of the wheel, designed to protect the inside of the tire from punctures and damage, as well as to form an optimal tire contact patch.
There are several types of treads: off-road, with a high pattern and powerful lugs; universal, suitable for driving on rough terrain and on asphalt; smooth, designed for driving mainly on rolled tracks. Tires with different seasons also have different tread designs.
Solid steel cord tires (TSMK)- automobile tires in which both the carcass and the breaker (the part of the tire located between the carcass and the tread) are pierced with steel wire. The all-steel tire is more expensive due to the fact that its production uses a complex technology that provides a strong bond between the cord and rubber. The tire canvas consists of several dozens of parallel steel cables - “pigtails”, which are pressed with rubber on both sides. The high cost of the SSC tire is offset by a longer service life. The design of the tire is such that a worn tread can be retreaded up to three times. This increases the life of the tire from 150,000 km to 500,000 km.
The main materials for the production of tires are rubber, which is made from natural and synthetic rubbers and cord. Cord fabric can be made from metal threads (metal cord), polymeric and textile threads.
The tire consists of: carcass, breaker plies, tread, bead and side part.
Textile and polymer cords are used in passenger and light truck tires.
Steel cord: depending on the orientation of the cord threads in the carcass, tires are distinguished:
- radial
- diagonal
In radial tires, the cords are located along the radius of the wheel. In diagonal tires, the cord threads are located at an angle to the wheel radius, the threads of adjacent layers intersect.
Radial tires are structurally more rigid, as a result of which they have a longer resource, have a stable shape of the contact patch, create less rolling resistance, and provide less fuel consumption. Due to the ability to vary the number of carcass plies (as opposed to the obligatory even number in diagonal ones) and the possibility of reducing plyiness, the total tire weight and carcass thickness are reduced. This reduces the heating of the tire during rolling - increases the service life. The breaker and tread also release heat more easily - it is possible to increase the thickness of the tread and the depth of its pattern to improve off-road flotation. In this regard, at present, radial tires for passenger cars have almost completely replaced diagonal ones.
Breaker located between the carcass and the tread. It is designed to protect the carcass from impacts, to stiffen the tire in the area of the tire contact patch with the road and to protect the tire and the driving chamber from through mechanical damage. It is made from a thick layer of rubber (in light tires) or crossed layers of polymer cord and (or) steel cord.
Tread necessary to ensure an acceptable coefficient of adhesion of tires to the road, as well as to protect the carcass from damage. The tread has a certain pattern, which, depending on the purpose of the tire, varies. High-flotation tires have a deeper tread pattern and lugs on its sides. The tread pattern and design of a road tire is determined by the requirements for the removal of water and dirt from the tread grooves and the desire to reduce rolling noise. But, nevertheless, the main task of the tire tread is to ensure reliable contact of the wheel with the road in adverse conditions such as rain, mud, snow, etc., by removing them from the contact patch along precisely designed grooves and grooves of the pattern. But the protector can effectively remove water from the contact patch only up to a certain speed, above which the liquid cannot physically be completely removed from the contact patch, and the car loses traction with the road surface, and hence control. This effect is called hydroplaning. There is a widespread misconception that on dry roads, the tread reduces the friction coefficient due to the smaller contact patch area compared to a tire without a tread (slick tire). This is not true, since in the absence of adhesion, the friction force does not depend in any way on the area of the contacting surfaces. Many countries have laws governing minimum tread heights on road vehicles, and many road tires have built-in wear indicators.
Board allows the tire to seal tightly on the wheel rim. To do this, it has side rings and is coated on the inside with a layer of viscous airtight (for tubeless tires) rubber.
Side part protects the tire from lateral damage.
Anti-skid spikes. In order to improve the safety of the car in conditions of ice and icy snow, metal anti-skid spikes are used. Riding on studded tires has noticeable features. On the move, the car becomes noticeably noisier, its fuel efficiency worsens. In snow-mud slush or in deep loose snow, the effectiveness of studs is low, and on hard dry or wet asphalt, studded tires even lose to “ordinary” ones: due to a decrease in the area of the tire’s contact patch with the road, the braking distance of the car increases by 5-10%. Although a 70 percent reduction in braking distance on ice is their undoubted advantage.
Tubeless tires(tubeless) are the most common due to their reliability, lower weight and ease of use (for example, a puncture in a tubeless tire will not cause much inconvenience on the way to a car service).
Marking - tire code.
Metric system
Example: LT205/55R16 91V
- LT (optional, mandatory designation according to DOT) - tire function (P - passenger car (Passenger car), LT - light truck (Light Truck), ST - trailer (Special Trailer), T - temporary (only used for spare tires))
- 205 — profile width, mm
- 55 — profile height to width ratio, %. If not specified, it is considered equal to 82%.
- R - the tire has a carcass of a radial type (if there is no letter, it is a diagonal type tire). A common mistake - R - is mistaken for the letter of the radius. Possible options: B - bias belt (diagonally belted tire. The tire carcass is the same as the bias tire, but there is a breaker, like a radial tire), D or not specified - a diagonal carcass type.
- 16 — landing diameter of the tire (corresponds to the diameter of the rim), inch
- 91 - load index (on some models, in addition to this, the load in kg may be indicated - Max load)
- V - speed index (determined according to the table)
Inch system
Example: 35×12.50 R 15LT 113R
- 35 - outer diameter of the tire, in inches
- 12.50 - tire width, in inches (note that this is the width of the tire itself, and not the tread part. For example, for a tire with a specified width of 10.5 inches, the width of the tread part will not be 26.5, but 23 cm, and the tread part of 26.5 cm will be tires with a specified width of 12.5.). If the outer diameter is not specified, then the profile is calculated as follows: if the tire width ends in zero (for example, 7.00 or 10.50), then the profile height is considered equal to 92%, if the tire width ends in a non-zero (for example, 7.05 or 10.55), then the profile height considered equal to 82%
- R - the tire has a radial type carcass
- 15 - tire diameter, in inches, the same as in the metric system
- LT - tire function (LT - light trucks, for light trucks)
- 113 - load index
- R - speed index
Convert from metric to inch and vice versa
| Metric system | Inch system |
|---|---|
D/E-C (205/55-16);
|
A×B-C (31×10.5-15);
|
| Conversion from metric to inch | Conversion from inch to metric |
|
|
Speed Indices
The speed category assigned to a tire based on the results of special bench tests implies maximum tire speed. During operation, the car must drive at a speed of 10-15% less than the maximum allowable.
|
Tire load indices
| Load index | Load index | ||
|---|---|---|---|
| 0 | 45 | 100 | 800 |
| 1 | 46,2 | 101 | 825 |
| 2 | 47,5 | 102 | 850 |
| 3 | 48,7 | 103 | 875 |
| 4 | 50 | 104 | 900 |
| 5 | 51,5 | 105 | 925 |
| 6 | 53 | 106 | 950 |
| 7 | 54,5 | 107 | 975 |
| 8 | 56 | 108 | 1000 |
| 9 | 58 | 109 | 1030 |
| 10 | 60 | 110 | 1060 |
| 11 | 61,5 | 111 | 1090 |
| 12 | 63 | 112 | 1120 |
| 13 | 65 | 113 | 1150 |
| 14 | 67 | 114 | 1180 |
| 15 | 69 | 115 | 1215 |
| 16 | 71 | 116 | 1250 |
| 17 | 73 | 117 | 1285 |
| 18 | 75 | 118 | 1320 |
| 19 | 77,5 | 119 | 1360 |
| 20 | 80 | 120 | 1400 |
| 21 | 82,5 | 121 | 1450 |
| 22 | 85 | 122 | 1500 |
| 23 | 87,5 | 123 | 1550 |
| 24 | 90 | 124 | 1600 |
| 25 | 92,5 | 125 | 1650 |
| 26 | 95 | 126 | 1700 |
| 27 | 97 | 127 | 1750 |
| 28 | 100 | 128 | 1800 |
| 29 | 103 | 129 | 1850 |
| 30 | 106 | 130 | 1900 |
| 31 | 109 | 131 | 1950 |
| 32 | 112 | 132 | 2000 |
| 33 | 115 | 133 | 2060 |
| 34 | 118 | 134 | 2120 |
| 35 | 121 | 135 | 2180 |
| 36 | 125 | 136 | 2240 |
| 37 | 128 | 137 | 2300 |
| 38 | 132 | 138 | 2360 |
| 39 | 136 | 139 | 2430 |
| 40 | 140 | 140 | 2500 |
| 41 | 145 | 141 | 2575 |
| 42 | 150 | 142 | 2650 |
| 43 | 155 | 143 | 2725 |
| 44 | 160 | 144 | 2800 |
| 45 | 165 | 145 | 2900 |
| 46 | 170 | 146 | 3000 |
| 47 | 175 | 147 | 3075 |
| 48 | 180 | 148 | 3150 |
| 49 | 185 | 149 | 3250 |
| 50 | 190 | 150 | 3350 |
| 51 | 195 | 151 | 3450 |
| 52 | 200 | 152 | 3550 |
| 53 | 206 | 153 | 3650 |
| 54 | 212 | 154 | 3750 |
| 55 | 218 | 155 | 3875 |
| 56 | 224 | 156 | 4000 |
| 57 | 230 | 157 | 4125 |
| 58 | 236 | 158 | 4250 |
| 59 | 243 | 159 | 4375 |
| 60 | 250 | 160 | 4500 |
| 61 | 257 | 161 | 4625 |
| 62 | 265 | 162 | 4750 |
| 63 | 272 | 163 | 4875 |
| 64 | 280 | 164 | 5000 |
| 65 | 290 | 165 | 5150 |
| 66 | 300 | 166 | 5300 |
| 67 | 307 | 167 | 5450 |
| 68 | 315 | 168 | 5600 |
| 69 | 325 | 169 | 5800 |
| 70 | 335 | 170 | 6000 |
| 71 | 345 | 171 | 6150 |
| 72 | 355 | 172 | 6300 |
| 73 | 365 | 173 | 6500 |
| 74 | 375 | 174 | 6700 |
| 75 | 387 | 175 | 6900 |
| 76 | 400 | 176 | 7100 |
| 77 | 412 | 177 | 7300 |
| 78 | 425 | 178 | 7500 |
| 79 | 437 | 179 | 7750 |
| 80 | 450 | 180 | 8000 |
| 81 | 462 | 181 | 8250 |
| 82 | 475 | 182 | 8500 |
| 83 | 487 | 183 | 8750 |
| 84 | 500 | 184 | 9000 |
| 85 | 515 | 185 | 9250 |
| 86 | 530 | 186 | 9500 |
| 87 | 545 | 187 | 9750 |
| 88 | 560 | 188 | 10000 |
| 89 | 580 | 189 | 10300 |
| 90 | 600 | 190 | 10600 |
| 91 | 615 | 191 | 10900 |
| 92 | 630 | 192 | 11200 |
| 93 | 650 | 193 | 11500 |
| 94 | 670 | 194 | 11800 |
| 95 | 690 | 195 | 12150 |
| 96 | 710 | 196 | 12500 |
| 97 | 730 | 197 | 12850 |
| 98 | 750 | 198 | 13200 |
| 99 | 775 | 199 | 13600 |
Additionally:
Tires must include the following information:
- The maximum allowable pressure (MAX PRESSURE).
Tire pressure significantly affects the behavior of the car on the road, safety at high speeds, as well as tread wear.
- Tire construction materials used in carcass and breaker construction
Color labels. Marks in the form of "dots" or "circles":
- red - the point of greatest power heterogeneity (the most rigid part of the tire). It is recommended to combine with the white dot on the wheel (if any);
- yellow - the lightest part of the tire (determined when monitoring tire imbalance).
These marks are necessary to minimize the mass of balancing weights during tire fitting.
Obsolete marks in the form of stripes in the side zone (used only in the United States):
- no - good quality;
- red - cosmetic defects;
- yellow - violation of the composition of the rubber mixture (no warranty);
- green - internal defects.
Purpose for specific operating conditions
- Winter - Winter tires.
- Aqua, Rain etc. - highly efficient on wet roads.
- M+S(Mud+Snow)- literally - "mud + snow" - suitable for driving in mud and snow. (Tyres)
- M/T(Mud Terrain)- mud landscapes.
- A/T(All Terrain)- All-season tyres.
- MAX PRESSURE - the maximum allowable pressure in the tire, in kPa.
- RAIN, WATER, AQUA(or pictogram "umbrella")- means that these tires are specially designed for rainy weather and have a high degree of protection against the effect of aquaplaning.
- Treadwear 380 - wear coefficient, determined in relation to the "base tire", for which it is equal to 100. The wear index is a theoretical value and cannot be directly related to the practical life of the tire, which is significantly influenced by road conditions, driving style, compliance with recommendations for pressure, camber adjustment and wheel rotation. The wear indicator is presented as a number from 60 to 620 with an interval of 20 units. The higher its value, the longer the protector withstands when tested according to the established method.
- Traction A — adhesion coefficient, has the values A, B, C. Coefficient A has the highest adhesion value in its class.
- Max load - the maximum load and then there are values in kilograms and pounds.
- PR(Ply Rating)- the strength (bearing capacity) of the frame is conditionally estimated by the so-called ply rate. The stronger the carcass, the more air pressure the tire can withstand, and therefore has a greater load capacity. For passenger cars, tires with a ply rating of 4PR and sometimes 6PR are used, and in this case the latter have the inscription "Reinforced", that is, "reinforced" (tires with increased load capacity).
- extra load(XL)- increased load index.
- Reinforced(Reinf or RF)- increased load index. On light trucks and minibuses, tires with 6PR and 8PR are most commonly used. The increased ply (that is, strength) of the tire may be indicated by the letter “C” (commercial), which is placed after the designation of the landing diameter (for example, 185R14C)
- TWI - the sign is located on the sidewall of the tire and shows the location of the marks of the residual height of the tread pattern in the main grooves. For the countries of the European Union and the Russian Federation, the remaining tread depth of a worn passenger tire must be at least 1.6 mm.
- ZP - Zero pressure (Zéro Pression), Michelin's commercial designation for tires with reinforced sidewalls. ZP: Ability to continue driving in the event of a puncture up to 80 km at speeds up to 80 km/h. ZP SR: Ability to continue driving in the event of a puncture up to 30 km at speeds up to 80 km/h.
- SST - self-supporting tire (Self Supporting Tires). Such tires can carry the load and continue to move after a puncture.
- Dunlop MFS(Maximum Flange Shield)- The system of maximum bead rim protection protects expensive wheels from damage on curbs and sidewalks - a rubber profile around the circumference of the tire, located on the lower part of the wall above the rim flange, forms a buffer zone.
- Studless - not subject to studding.
- Studdable - to be studded.
In addition, quality standards are indicated on the tires (the letter “E” in a circle is the European standard, “DOT” is the American standard).
The pneumatic tire, which is one of the most important elements of a car, consists of a tire and a tube located on the wheel rim. The tire perceives the vertical load from the weight of the car, and all the forces that occur in the contact patch of the tire with the road when accelerating, braking and turning the car. The tire also absorbs and softens the impacts that occur when the vehicle is driven on the road. During the movement of the car, the elastic pneumatic tire in the lower part is deformed, small bumps in the road are absorbed due to tire deformation, and large ones cause smooth movement of the wheel axle. This ability of the tire is called smoothing. The smoothing ability of the tire is due to the elastic properties of the compressed air that fills the tire. When a tire deforms, energy losses inevitably occur due to internal friction in the tire material. Internal friction increases the temperature of the tire, which adversely affects its durability. The greater the deformation of the tire, the greater the energy costs for internal losses and the greater the power spent on the movement of the car. The properties and performance of a tire largely depend on its design.
TIRE CONSTRUCTION
The modern tire has a rather complex design (Fig. 4.6). The main material for the manufacture of tires is rubber and a special fabric - cord. If you make a tire only from rubber, then when it is filled with air, it will significantly change its size and shape. The rubber used for the production of tires is made from rubber (natural and synthetic), to which various fillers are added during the production process: sulfur, soot, resins, etc.
In the manufacture of pneumatic tires for the first cars, only natural rubber was used, which was obtained from the resin of rubber trees. Synthetic rubber was first obtained in our country. This invention belongs to academician S. V. Lebedev, who in 1931-1932 was the first in the world to develop a technology for the production of synthetic rubber. In order for the elastic rubber with fillers to turn into elastic rubber, it must undergo a vulcanization process (the combination of sulfur with rubber, which occurs at elevated temperatures). Tires are vulcanized in special molds, the inner surface of which corresponds to the outer surface of the tire. Before the tire enters the mold, it is assembled from its constituent elements on special machines.
The tire structurally consists of a carcass, belt, tread, sidewall and bead. The carcass of a tire is made up of several layers of rubberized cord.
which is a tissue consisting of longitudinal and rare transverse threads closely spaced to each other. The stronger the cords, the more durable the tire. Synthetic fiber, glass fiber and steel threads (metal cord) are currently used as threads for cord production. With an increase in the cord layers in the carcass, the strength of the tire increases, but at the same time its mass increases and the rolling resistance increases.
Rice. 4.6. Pneumatic tire design: 1 - two-layer protector (soft rubber is highlighted in red); 2 - a special form of the bead ring; 3 - shoulder parts resistant to cuts; 4 - protective side layer
The bead of the tire has a certain shape, necessary for a tight fit on the rim of the forest. The beads of the tire should not stretch to ensure a tight fit of the tire on the rim and to prevent the possibility of the tire coming off the rim. For this purpose, split or continuous bead rings made of several layers of strong steel wire are inserted inside the tire beads. Outside, the sides are covered with a rubberized cord and a thin layer of rubber.
The sidewall of the tire is a thin layer of elastic and durable rubber applied to the carcass. It protects the tire from lateral damage and moisture.
The tread of the tire provides the grip of the tire with the road and protects the carcass from damage. For its manufacture, durable, wear-resistant rubber is used. The outer part of the tread is made in the form of a clear pattern, under which there is a so-called sub-groove layer. The tread pattern is determined by the type and purpose of the tire.
The breaker is a special belt made of several layers of rubberized cord, which is located between the carcass and the tread. The shape of the contact patch between the tire and the road largely depends on the design of the breaker. The breaker protects the carcass from shocks and impacts and transmits forces to the various parts of the tire.
The inner surface of the tire is covered with a thin layer of rubber. The composition of the rubber used for this layer can be different depending on the type of tire (tube or tubeless).
In a tube tire, a tube is used to hold compressed air, which is an elastic, air-tight shell in the form of a closed tube. In order for the tube not to form wrinkles when mounting the tire on the rim, the dimensions of the tube must be somewhat smaller than the internal dimensions of the tire. Therefore, the chamber filled with air is in a stretched state. To inflate and release air, the chamber is connected to a valve (Fig. 4.7) - a special valve, the shape and dimensions of which depend on the type of tire. When mounting a tire on a wheel rim, the valve must pass through a special hole made in this rim.
Tubeless tires outwardly differ little from tube tires (Fig. 4.8). The inner coating of such a tire should be made of a layer of airtight rubber with a thickness of 2-3 mm, and on the outer
Rice. 4.7. Chamber vent: 1 - spool rod; 2 - threaded head; 3 - bushing; 4 - sealant; 5 - upper cup; 6 - sealing ring of the spool; 7 - lower cup; 8 - valve body; 9 - spool spring; 10 - guide cup; 11 - rubberized casing
The top of the bead is covered with elastic rubber, which ensures tightness when the tire fits on the rim. The valve of a tubeless tire forms a tight connection when it is installed in the hole in the wheel rim. When a tubeless tire is punctured with a small object, this object stretches the air
Rice. 4.8. Wheel design (a) with tubeless tyre: 1 - protector; 2 - sealing airtight rubber layer; 3 - frame; 4 - wheel valve; 5 - rim; (b) wheels with a tube tire: 1 - wheel rim; 2 - camera; 3 - tire (tire); 4 - valve
hone-tight inner rubber layer of a tubeless tire and is wrapped around it. In this case, the air from the tubeless tire comes out very slowly, in contrast to the chamber, in which the tube is in a stretched state, and, therefore, any damage to it causes an increase in the resulting hole. Therefore, tubeless tires are safer.
Small damage to tubeless tires can be repaired without removing the tire from the rim by sealing the resulting hole with a special material.
An important advantage of tubeless tires compared to tube tires is their lower weight and heating during movement. The latter is due to the absence of friction between the chamber and the tire and better cooling. Since tire wear is highly dependent on operating temperature, tubeless tires last longer. It is not recommended to install tubes in tubeless tires, because when inflating the tube between the tire and the tube, air cushions can form, which will interfere with heat removal and lead to local overheating of the tire. The disadvantages of tubeless tires include the greater difficulty of repairing on the road in case of severe damage, as well as the need for high cleanliness and smoothness of the rim flange to ensure tightness.
TIRE CLASSIFICATION
Car tires differ in purpose, dimensions, design and profile shape. By appointment, car tires are divided into two groups: for passenger cars and for trucks. Tires designed for passenger cars can be used
on light duty trucks and related trailers.
The design of the tires is determined by the location of the cords in the carcass. There are two structural types of car tires: diagonal and radial (Fig. 4.9).
For a long time, only diagonal tires were used on cars, until Michelin developed a radial tire design in 1947. Most vehicles today are equipped with radial tires. In the carcass of a diagonal tire, the cord layers are placed at an angle to the wheel radius. Threads of neighboring carcass layers intersect. There should be only an even number of cord layers in the carcass. The radial tire has no
Rice. 4.9. The design of the diagonal (a) and radial (b) tires: 1 - sides; 2 - bead wire; 3 - frame; 4 - breaker; 5 - sidewall; 6 - protector
Rice. 4.10. Structural elements and main dimensions of the tire: D - outer diameter; H is the height of the tire profile; B - tire profile width; d - landing diameter of the wheel rim (tire); 1 - frame; 2 - breaker; 3 - protector; 4 - side of wine; 5 - board; 6 - bead wire; 7 - filling cord
These cords in the carcass are located at the shortest distance between the sides along the radius of the wheel. The number of layers in the frame may be odd.
The location of the threads in the radial tire provides better constancy of the shape of the contact patch of the tire with the road, less movement of the tread elements and, as a result, such tires heat up and wear out less. This factor has become decisive in the transition from diagonal tires to radial. In addition, modern radial tires have lower rolling resistance and provide better vehicle stability and handling.
According to the shape of the tire profile, there can be a regular profile, wide-profile, low-profile, ultra-low-profile, arched and pneumatic rollers. The profile of conventional tires is close to a circle (Fig. 4.10). The profile height to width ratio of conventional tires is over 90%.
In general, there is a tendency to decrease the ratio of the height of the profile to its width (Fig. 4.11).
If the tires of the first cars had a regular profile, then the tires of modern cars, especially passenger cars, are low profile or ultra-low profile. in which the ratio of profile height to width is from 70% to 60% or less.
Reducing the height of the sidewalls of a tire while maintaining the same tire width makes it possible to make a larger wheel without increasing the overall diameter of the tire. This increases the space for
Rice. 4.11. Changing the profile of car tires
accommodating a larger, and therefore more efficient, disc brake. Trailers and semi-trailers of modern road trains are often equipped with ultra-low profile tires to lower the floor and increase the useful cargo volume of these vehicles. Reducing the height of the profile increases the rigidity of the sidewalls of the tire, and this provides a faster response of the tire to steering commands. Reducing the deformation of the sidewalls of the tire reduces the amount of heat generated and ensures safer operation at higher speeds. On the other hand, the sidewalls become stiffer, which leads to a deterioration in the smoothing ability of the tires, and the shape of the contact patch becomes shorter and wider. These tires can adversely affect the vehicle's handling. These shortcomings have limited the widespread use of ultra-low profile tires for mass-produced vehicles, which typically use tires with a profile height-to-width ratio of 60, 65, and 70%. There are passenger cars equipped with ultra-low profile tires, in which the profile height is 30% of its width.
Wide-profile and arched tires are installed on the wheels of trucks in order to improve their cross-country ability. One such tire can replace dual tires.
The best passability on a soft supporting surface (snow, sand, mud) is provided by pneumatic rollers with a barrel-shaped profile and high elasticity. Profile height to width ratio is 25-40 %. Pneumatic rollers are produced only tubeless, they operate at very low air pressure (about 0.01-0.05 MPa). High resilience and low internal air pressure in pneumatic rollers provide very low ground pressure.
