The purpose of the wheels is to connect the car with the road, ensure the movement of the car, change the direction of movement and transfer vertical loads from the car to the road. Simply put, it is thanks to the wheels that we can move and drive the car, so the behavior of the car on the road directly depends on the correct choice of wheels.
There are the following types of wheels:
- presenters;
- managed;
- combined (leading and controlled);
Drive wheels are so named precisely because they convert engine thrust into forward movement car, transferring all the moments and forces to the road. steered wheels are solely responsible for controlling the direction of the vehicle. And if the wheel receives traction from the engine, and is also responsible for the direction of movement, then it is combined.
Automobile wheel assembly (Figure 6.20) consists of a pneumatic tire, rim, hub and connecting element- disk.
Figure 6.20 Car wheel. Cross section.
The pneumatic tire is the most important element in wheel design. If we imagine a wheel without a pneumatic tire - rigid, for example, wooden, then it is easy to assume that when such a wheel rolls on a hard road, the trajectory of the axle will copy the profile of the road. The impact of the wheel on the unevenness of the road in this case will be completely transmitted to the suspension. And everything looks very different when a pneumatic tire is mounted on the wheel. At the point of contact, an elastic tire (usually made on the basis of rubber and various additives - from soot to silicon oxide) is deformed. At the same time, small irregularities, deforming the tire, do not affect the position of the wheel axle.
If the wheel runs into more significant obstacles, then strong shocks cause increased deformation of the tire and smooth movement of the wheel axle. The ability of a pneumatic tire to smoothly change the negative effect of road surface defects on the wheel axle is called smoothing.
The smoothing effect is provided by the elastic properties of the compressed air in the tire.
Note
When part of the tire rolls out of contact with the road surface, a fraction of the energy expended in deformation of the tire is spent on internal friction in the rubber, turning into heat. Heating adversely affects the properties of tires, as a result - accelerated wear.
The energy loss depends on the design of the tire, the internal air pressure in it, the load, the speed of movement and the transmitted torque. With an increase in tire deformation, internal friction losses also increase, the consequence of this is an increase in the power expended on the movement of the car.
To reduce deformation and irreversible losses, the air pressure in the tire must be increased. However, in order to meet the requirements for ensuring a high smoothing ability of the tire, on the one hand, and to reduce irreversible losses due to internal friction, on the other hand, the air pressure in tires of each type is set taking into account their design features and operating conditions.
The air pressure in the wheel tire is the most important performance indicator and each manufacturer is installed in accordance with the design and direct purpose of the tire.
The rim is usually mounted on the wheel hub, which, in turn, is mounted in rounded fist and rotates freely roller bearings. A disk is made from sheet metal by stamping and subsequent welding of elements. Wheels can be cast from light alloy materials (for example, aluminum and magnesium alloy), or they can be forged, which combine light alloy material and stamping.
Pneumatic tire
Attention
Operating a tire with a tread height that is less than the limit allowable rate established by the rules traffic, FORBIDDEN! Minimum allowable height tread:
- for cars - 1.6 mm;
- For trucks with a carrying capacity of more than 3.5 tons - 1.0 mm;
- for buses - 2.0 mm;
- for motorcycles - 0.8 mm.
Bus device
Note
It is worth noting that at the moment tires are divided into two types: chamber and tubeless. Tires of the first type have a special chamber into which air is pumped. In tubeless tires, the tire is mounted on the rim, sealed and inflated with air.
Figure 6.21
The rubber used to make tires consists of rubber (natural or synthetic) to which sulfur, soot, tar, chalk, recycled old rubber and other impurities and fillers are added. The tire consists of a tread, a cushion layer (with a belt), a carcass, sidewalls and landing beads with cores (force ring), as shown in the corresponding figure 6.21. The carcass serves as the basis of the tire: it connects all its parts into one whole and gives the tire the necessary rigidity, while it has high elasticity and strength. The tire frame is made of several layers of cord 1-1.5 mm thick. The number of cord plies is even to evenly distribute structural strength and is typically 4 or 6 for passenger car tires and 6-14 for truck and bus tires.
Interesting
With an increase in the number of cord layers, the strength of the tire increases, but at the same time its mass increases and the rolling resistance increases, which is unacceptable.
The cord is a special fabric consisting mainly of longitudinal threads with a diameter of 0.6 - 0.8 mm with very rare transverse threads. Depending on the type and purpose of the tire, the cord can be cotton, viscose, nylon, perlon, nylon and metal. The cheapest of all is cotton cord, but it has the lowest strength, which, moreover, decreases significantly when the tire is heated. The strength of the nylon cord is approximately 2 times higher than that of cotton, and the perlon and nylon cords are even higher. The most durable is a metal cord, the threads of which are twisted from high-quality steel wire with a diameter of 0.15 mm. The strength of the metal cord is more than 10 times higher than that of cotton cord, and it does not decrease when the tire is heated. Tires made from this cord have a smaller number of layers (1-4), lower weight and rolling loss*, and are more durable. The cord threads are placed at a certain angle to the plane drawn through the wheel axle. The angle of inclination of the threads depends on the type and purpose of the tires. It is 50-52° for conventional tires.
Note
* Rolling loss. Whatever one may say, while driving, more precisely when rolling, friction occurs in all layers of the tire and, as a result, the tire is first deformed, as it were, with a delay, and then, with the same delay, returns to its original position. As a result of this not cunning action, the tire begins to heat up. If it heats up, then it simply spends part of the energy applied to it intended for rolling into an empty one. Scientists from many laboratories are studying the issues of this problem in order to reduce rolling losses.
The cushion layer (and breaker) connects the tread to the carcass and protects the carcass from shocks and impacts perceived by the tread from road irregularities. It usually consists of several layers of sparse rubberized cord, the thickness of the rubber layer in which is much greater than that of the carcass cord. The thickness of the cushion layer is 3-7 mm, and the number of cord layers depends on the type and purpose of the tire.
The sidewalls protect the frame from damage and moisture. They are usually made of tread rubber with a thickness of 1.5-3.5 mm.
The beads hold the tire securely on the rim. Outside the bead there are one or two layers of rubberized tape that protects them from abrasion on the rim and from damage during mounting and dismounting of the tire. Inside the boards there are steel wire cores. They increase the strength of the beads, protect them from stretching and prevent the tire from jumping off the wheel rim.
The bladder keeps the compressed air inside the tire. It is an elastic rubber shell in the form of a closed tube. For a snug fit (no wrinkle) inside the tire, the chamber dimensions are slightly smaller than the inner cavity of the tire. Therefore, the chamber filled with air is in the tire in a stretched state. The tube wall thickness is usually 1.5-2.5 mm for passenger car tires and 2.5-5 mm for truck and bus tires. Radial marks are made on the outer surface of the chamber, which contribute to the removal of air remaining between the chamber and the tire after mounting the tire. The chambers are made of high-strength rubber.
Tubeless tire features
A tubeless tire does not have a tube or rim tape and acts as both a tire and a tube at the same time. According to the device, it is very close to the tire of a tube tire and appearance almost indistinguishable from her. A feature of a tubeless tire is the presence on its inner surface of a sealing airtight rubber layer with a thickness of 1.5-3.5 mm.
Note
The tubeless tire carcass material is also characterized by high airtightness, since it uses a viscose, nylon or nylon cord, the airtightness of which is 5-6 times higher than that of a cotton cord.
Note
The seat diameter of the tubeless tire is reduced, it is mounted on a sealed rim.
Tread pattern
Attention
According to the rules of the road, it is forbidden to install tires of different sizes and with different tread patterns on the same axle.
Purpose
Under ideal conditions, there should be no tread at all (look at the slicks of formula cars) so that the contact area of the tire with the road surface is maximized. However, ideal conditions are when the road is covered with asphalt concrete, and dry. As soon as even a small layer of water appears on the surface or the surface becomes simply wet, the coefficient of grip * of the tire with the road will drop sharply, contact will be lost and the driver will lose control of the car. In order for this very water to be diverted to when it hits a surface with a layer of water (one might say, forcibly), the tire is full of a “Christmas tree” tread. If the tire is designed to run in winter period, which means that the shape of the tread will be appropriate - an increased number of lamellas and mud traps.
Note
* The force with which the wheels "cling" to the road is characterized by the coefficient of adhesion of the tires to the road. The coefficient of friction is the ratio of the grip force of the wheels with the road to the weight that falls on this wheel. The coefficient of adhesion with the road is crucial when braking and accelerating the car. The higher the coefficient of adhesion of the wheel, the higher will be the intensity of acceleration and deceleration of the car.
Tire tread patterns
- Non-directional pattern (Figure 6.22) - a pattern symmetrical about the vertical axis of the wheel passing through its axis of rotation. This is the most versatile pattern, which is why the majority of tires are produced with this pattern.
- Directional pattern (Figure 6.23) - a pattern symmetrical about a vertical axis passing through central part protector. Among the advantages of this pattern is an improved ability to drain water from the contact patch with the road and reduced noise.
- Asymmetric pattern (Figure 6.24) - a pattern that is not symmetrical about the vertical axis of the wheel. Such a pattern is used to implement various features in a single bus. For example, the outer side of a tire performs better on dry roads, while the inner side performs better on wet surfaces.
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Tire marking
There are two concepts related to each tire model: size and indexes.
For example, the specified size is 255/55 R16, where
255 - tire profile width in mm;
55 - the ratio of the height of the tire profile (from the landing rim to the outer edge of the wheel) to the profile width in percent.
Note
It is noteworthy that the smaller this figure, the wider the tire.
R - radial cord construction, composite cords in carcass layers have a radial arrangement (directed from bead to bead);
16 - rim diameter in inches (1 inch = 2.54 cm).
The indices indicate the parameters of the maximum load per tire in kilograms and the speed index - the maximum allowable speed movement in km / h, as well as additional indices characterizing the properties of a particular tire.
Figure 6.25
| Speed index | Maximum speed, km/h |
| L | 120 |
| M | 130 |
| N | 140 |
| P | 150 |
| Q | 160 |
| R | 170 |
| S | 180 |
| T | 190 |
| U | 200 |
| H | 210 |
| V | 240 |
| W | 270 |
| Y | 300 |
| Z | Over 240 |
There are two types of markings: for domestic tires and for foreign tires.
Domestic tire labeling
In accordance with GOST, the following mandatory inscriptions are applied to the tire:
- trademark and (or) name of the manufacturer;
- name of the country of manufacture in English - "Made in ...";
- tire designation;
- trade mark (tire model);
- bearing capacity index (carrying capacity);
- speed category index;
- "Tubeless" - for tubeless tires;
- "Reinforced" - for reinforced tires;
- "M+S" or "M.S" - for winter tires;
- "All seasons" - for all-season tires;
- date of manufacture, consisting of three digits: the first two indicate the week of manufacture, the last - the year;
- "PSI" - pressure index from 20 to 85 (only for tires with index "C");
- "Regroovable" - if it is possible to deepen the tread pattern by cutting;
- approval mark "E" indicating the approval numbers and the country that issued the certificate;
- GOST number;
- national mark of conformity to GOST (it is allowed to apply only in the accompanying documentation);
- serial number of the bus;
- direction of rotation sign (in the case of a directional tread pattern);
- "TWI" - location of wear indicators;
- balancing mark (except for tires 6.50-16С and 215/90-15С supplied for operation);
- technical control stamp.
Foreign tire marking
Other markings may be present on such tires:
- "Tous terrain" - all-weather;
- "R + W" (Road + Winter) - road + winter (universal);
- "Retread" - restored;
- "Inside" inner side;
- "Outside" - the outer side;
- "Rotation" - direction of rotation (for tires with a directional pattern);
- "Side facing inwards" - inner side (for asymmetric tires);
- "Side facing outwards" - outer side (for asymmetric tires);
- "Steel" - designation of the presence of steel cord;
- "TL" - tubeless tire;
- "TT" or "MIT SCHLAUCH" - tube tire.
Run flat tires
Run-flat technology is used in the production of expensive car tires. These tires have reinforced sidewalls. The presence of durable inserts in the sidewall of the tire made of rubber special composition allows it to support the weight of the vehicle even when flat.
On a flat tire run-flat tires you can drive about 80 km if the car is fully loaded. If only the driver is in the car, then you can drive on a flat tire for about 150 km (at a speed of no more than 80 km / h). Being able to drive at least 80 km on a flat tire without disc and suspension damage allows drivers to avoid the difficult and unsafe tire change in traffic. Engineers have ensured that the tire after vulcanization can be reused.
Figure 6.26
Note
For safety reasons, run-flat tires can only be installed on vehicles with electronic control exchange rate stability and tire pressure sensors that warn of changes in tire pressure.
Wheel disks
Disc designation
Figure 6.27
It is useful to know the tire marking, since the tire is put on a disk, which also has its own marking, and this marking must correspond to the selected tire.
For example, marking on a disk "8.5J x 17 H2 5/112 ET 35 d 66.6" has the following decoding:
Note
The designation of the disc is applied to the inner surface, must be duplicated on the packaging and be in the accompanying documentation or stickers.
8.5 - rim width in inches. The size given should be without fail correlate with tire width;
Attention
A tire whose width does not match the width of the rim may come off while driving.
x - sign between symbols width and fit diameter indicates that the wheel rim is one-piece;
17 - wheel rim diameter in inches, which must necessarily correspond to the tire diameter;
Note
On cars wheels with a diameter of 12 to 32 inches are used, the most common diameters are 14-16 inches.
J is an encoding letter informing about design features side flanges of the rim (angles of inclination, curvature radii, etc.);
H2 - the letter "H" (short for the English word "Hump") indicates the presence of annular protrusions (so-called humps) on the rim shelves that keep the tubeless tire from jumping off the disk. Often there are two humps on the wheel (designation “H2”), however, there can be one hump (designation “H”), they can have a flat shape (FH - “Flat Hump”), be asymmetric (AH - “Asymmetric Hump”) , combined (CH - "Combi Hump");
5/112 - PCD ("Pitch Circle Diameter" The diameter formed by the centers of the holes reinforcing the wheel) - the number "5" indicates the number of mounting holes in the disk for bolts or nuts (the most common wheels with a number of mounting holes from 4 to 6, less often - 3, 8 or 10), "112" is the diameter of the circle formed by the centers of the mounting holes, in mm. There is a certain number of such diameters - for example, 98; 100; 112; 114.3; 120; 130; 139.7 and some others. Often they are used by manufacturers by tradition or as the most suitable for cars of a certain purpose - for example, the size of 139.7 is typical for pickups and SUVs;
ET - designation of the disc offset size in mm;
Note
Departure of the wheel disc (see Figure 6.27) is the size between the landing (attachment) plane of the wheel disc, which is adjacent directly to the wheel hub and the axis of symmetry of the wheel rim.
If the plane of contact with the wheel hub is "outside" relative to the axis of symmetry, the wheel offset is called positive, for example, ET35; if "from the inside" (closer to the car) - the departure is negative, for example, ET-20. In other words, than more wheel protrudes beyond the body, the smaller the overhang value. If the offset designation is zero, then the surface of contact with the wheel hub lies on the axis of symmetry of the disc rim.
Attention
Fitting wheels with a shorter offset than standard offset can give a different look to the vehicle, but this turn of events can adversely affect both handling and wheel bearing life.
d - hub diameter or diameter central hole in mm.
Note
In the best possible way given diameter must match the diameter of the seat belt on the vehicle hub.
Attention
It is always necessary to use only special bolts and fastening nuts for fastening the wheels.
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Read it, it's interesting. By the way, there are also tables. Today I want to talk about bias and radial tires. It is clear that the topic is hackneyed and there is a lot of information on the Internet on this issue. However, a lot of abstruse articles written technical language not quite clear to the average layman. Today I will try to talk about their structure, in simple human language. I won't wait, let's get started...
The first type (the arrangement of threads in the structure diagonally) is now very rarely seen on the roads. "Why?" - ask you a question. Yes, everything is simple, the advantages of radial types are much greater, so many, yes, almost all manufacturers refuse to produce diagonal tires. Let's talk about the name.
Where did the name diagonal and radial tires? It comes from the structure of the rubber itself. The basis of any wheel is a frame, which is made of layers, in which there are fabric threads. It is the fabric threads that provide the necessary strength and stability of the structure. This is the base of the wheel. Next comes the so-called top layer, on which the tread itself is built, the so-called BREAKER, into which a metal power cord is implanted, this is the power part of any wheel. The differences lie precisely in the lower first layer. Or rather in his direction in the design.
Tire structure
Bias tires
As the name implies, diagonal - have diagonal layers of fabric threads in their design, with each next layer opposite to the direction of the previous one, in an overlap. Due to the need to cross two adjacent paths, the number of layers of thread must be even, for example 4, 6 or 8. Usually there are 4 layers. In simple words: — fabric layers overlap with each other. I think this is understandable.
Now the pros and cons
pros
Diagonal has simple design, and consequently a cheap price. The side walls of such tires are characterized by increased strength, side cuts can be repaired on such wheels, and without fear of driving, and not putting it on a spare tire. Also, diagonal types better “swallow” small pits, seams and road crossings.
Minuses
When subjected to loads severe deformation(collapse), the tread is wrinkled, which worsens the coupling and speed properties tires. resistance to high speeds much lower than radial.
Radial tires
In radial - fabric threads in the structure of the wheel do not intersect with each other. And they go horizontally from one side to the other. It should be noted that it is these tires that can be chambered and tubeless. The upper part (BREKER) plays the main role. Sometimes the breaker layer has up to 25 metal frame layers in its structure (which consist of steel or brass wires with a diameter of 0.1 to 0.2 mm). The metal cord has a much higher strength than the textile cord, has low extensibility, as well as better thermal conductivity. Thanks to all this, we can say that the radial type keeps its shape perfectly.
pros
Excellent road holding, and accordingly they are safer at high speeds and heavy loads. They have improved grip characteristics, both on wet and dry pavement. Resistance to damage and punctures in the tread area.
Minuses
The cost is higher due to the complex structure. Sidecord, soft, more prone to damage than the opponent. With a side cut, a radial tire is undesirable for everyday use. As a rule, it is removed to the reserve.
Despite the fact that diagonal tires are cheaper and hold a side impact well, they have practically disappeared from the market. Radial tires because of their strong tread carcass, and resistance to high loads and speeds, as well as excellent traction, they won this battle.
Now the guys watch a useful video on the topic, there is a conversation about motorcycle wheels manufactured by Michelin, but the information is presented very clearly, we look.
These are the devices, I think my article was useful to you, watch and read our automotive website, subscribe to updates on social networks.
Car tires are classified:
- by appointment,
- profile form,
- dimensions,
- designs,
- sealing principle.
By appointment tires are divided for use into:
Passenger cars;
- light trucks;
- minibuses and trailers for them, in all climatic zones at an ambient temperature of -45 C° to +55 C°. Truck tires are used on trucks, trailers, semi-trailers, buses, trolleybuses, in all climatic zones at ambient temperatures up to -45 ° C.
By way of sealing tires are divided into:
Chamber tires, in which the air cavity is formed by the chamber;
- tubeless tires, in which the air cavity is formed by the tire and the wheel rim. Sealing the air cavity is achieved by a sealing layer of rubber applied to the inner surface of the tire and having an increased gas impermeability.
1. Tube tire
2. Tubeless tire
The main advantage of a tubeless tire is the long-term pressure retention during a puncture, and therefore safety. A tube tire loses pressure almost instantly when it gets punctured, because the air quickly escapes through the valve hole in the wheel rim. And from a tubeless tire, air comes out only at the puncture site, and if the hole is not too large (from a nail, for example), then pressure is lost very slowly. In addition, a tubeless tire is much lighter than a tubed one, which means that it loads the suspension and wheel bearings less, and also heats up less during long high-speed driving.
By dimensions tires are divided into:
Large-sized, with a profile width of 350 mm (14 inches) or more, regardless of the bore diameter;
- medium-sized, with a profile width from 200 mm to 350 mm (from 7 to 14 inches) and landing diameter at least 457 mm (18 inches);
- small-sized, with a profile width of not more than 260 mm (up to 10 inches) and a bore diameter of not more than 457 (18 inches).
profile shape cross-section (depending on the nominal ratio of the height of the tire profile "H" to its width "B") are divided into tires:
regular profile - H / B over 0.89;
low profile - H/B = 0.7 - 0.88; 
wide profile - H/B = 0.6 - 0.9; 
ultra low profile - H/B =< 0,7;
arched - H / B = 0.39 - 0.5;
pneumatic rollers - H/B = 0.25 - 0.39.
Low profile and ultra low profile tires are available for cars, trucks, buses and trolleybuses. These tires have a lower profile height, which increases the stability and controllability of the car when driving.
Wide profile tires are used on heavy-duty vehicles, all-wheel drive vehicles and trailers. Their use allows you to increase the cross-country ability of the car, reduce the consumption of materials, since they are often used on one tire instead of dual ones.
Arched tires are available tubeless. They are installed on rear axle 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.
To reduce the pressure on the ground, instead of conventional wheels, pneumatic rollers are used, which are barrel-shaped "pneumatics" with low internal air pressure. Their diameter is 1 m with a width of 1-1.5 m. Such rollers easily adapt to road irregularities and absorb all shocks, so all-terrain vehicles equipped with them do not need suspension at all. Usually pneumatic rollers are combined in pairs into front and rear carts. Torque is transmitted through a gear system. Such machines are able to easily move through swamps, sand, snow, and even along the railway track.
Tire construction
frame(bandage) - the most important power part of the tire, which ensures its strength, perceives internal air pressure and transfers loads from external forces acting from the side of the road to the wheel. The carcass consists of one or more layers of rubberized cord, usually fixed on the bead rings . The cord is a fabric consisting of thick warp threads and thin rare weft threads, made on the basis of natural or synthetic fibers, or thin steel threads (metal cord).
Breaker(layers of steel cord) is a belt covering the tire carcass along its outer part, directly under the tread. It consists of several layers of rubberized metal or other cord. The breaker serves to improve the connections of the carcass with the tread, prevents its delamination under the action of external and centrifugal forces, absorbs shock loads and increases the resistance of the frame to mechanical damage.
Tread- this is the part of the tire that is in direct contact with the road and is a thick layer of rubber, consisting of an outer relief part and a continuous strip under it. The relief pattern of the tread largely determines the suitability of the tire for different road conditions. The tread provides traction and protects the carcass from damage.
shoulder area- the part of the tread located between the tread and the sidewall of the tire. It increases the lateral stiffness of the tire, takes part of the lateral loads transmitted by the treadmill and improves the connection between the tread and the carcass.
sidewall- part of the tire located between the shoulder area and the bead, which is a relatively thin layer of elastic rubber, which is a continuation of the tread on the side walls of the carcass and protects it from moisture and mechanical damage. On the sidewalls there are designations and tire markings.
Board- the rigid part of the tire, which serves to fasten and seal it (in the case of tubeless) on the wheel rim. The basis of the bead is an inextensible ring woven from rubberized steel wire. Consists of a layer of carcass cord wrapped around a wire ring and a round or profiled rubber filler cord. The steel ring gives the board the necessary rigidity and strength, and the filler cord gives solidity and an elastic transition from the rigid ring to the sidewall rubber. On the outer side of the bead there is an onboard tape made of rubberized fabric, or cord, which protects the bead from abrasion against the rim and damage during installation and dismantling.
1. Bead wire ring
2. Sidewall
3. Longitudinal tread groove
4. Shoulder protector
5. Central rib protector
6. Protector
7. Nylon belt layer
8. 2nd layer of steel breaker
9. 1st layer of steel belt
10. 2nd layer of textile frame
11. 1st layer of textile frame
12. Side tape
13. Heel board
14. Bead base
15. Toe board
16. Filler cord
17. Sealing layer
18. Undergroove tread
Tire composition
The tire structure contains various components in various combinations. These components differ from each other depending on the tire size and type (summer or winter tires).
Below they are indicated on the 205/55 R 16 ContiPremiumContact tire taken as an example. The tire shown here weighs 9.3 kg.
Rubber (natural and synthetic) - 41%
Fillers (soot, silicates, carbon, chalk…) - 30%
Reinforcers (steel, rayon, nylon) - 15%
Softeners (oils and resins) - 6%
Curing chemicals (sulfur, zinc oxide, various other chemicals) - 6%
Anti-aging chemicals (against ozone and material fatigue) - 1%
Others - 1%
By design tires are divided into:
Diagonal, in which the carcass and breaker cord threads intersect in adjacent layers, and the angle of inclination of the threads in the middle of the treadmill in the carcass and breaker is from 45 ° to 60 °;
- radial, (radial tires come with a removable tread) in which the angle of inclination of the carcass cord threads is 0 °, and the breaker is at least 65 °. These tires have a carcass with a smaller number of cord layers than diagonal ones, a powerful breaker is often made of metal cord, which provides less circumferential deformation of the tire during rolling and tread slippage in contact with pavement. And as a result, radial tires have reduced heat generation and lower rolling losses, longer service life, maximum load and allowable speed.
Radial tires are produced in three types: with metal cord in the carcass and breaker (SMC); with a cord made of synthetic or natural fibers in the carcass and a metal cord in the breaker; with a cord of natural fibers in the carcass and breaker.
1. Radial design
2. Diagonal design
Types of tread patterns
Road (D), summer - the most common. They are distinguished by clearly defined longitudinal grooves to drain water from the contact patch of the tread with the road, weakly expressed transverse grooves and the absence of a micro-pattern. In addition, they have a mandatory smooth (rounded) transition from the tread to the sidewalls. Tires of this type provide maximum grip on dry and wet roads, have maximum wear resistance and are best suited for high-speed driving. For movement along dirt roads(especially wet) and in winter they are of little use.
All-weather - well adapted to work on dry and wet pavement, are satisfactorily adapted to winter roads more wear than summer. The tread pattern of an all-season tire is more branched, and the elements of the pattern are grouped into a well-defined "track" and separated by grooves of different widths; on the elements of the picture - "checkers" - there are narrow slots of an additional micro-pattern. As a rule, these tires are marked all season, or conventional signs(snowflake or drop).
Universal (U) - (according to domestic terminology) are designed to work on roads of any quality. Moreover, it can be quite difficult to draw a clear line between them and all-weather ones. They differ primarily in a deeper and more branched tread pattern. By Western standards, tires of the M + S type (Mud and Snow - mud and snow) can be attributed to universal tires in the version with less dissected grooves of the tread pattern, with or without a weakly expressed micropattern.
Cross-country ability (PP) - consists of high lugs dissected by wide grooves. Tires with a tread pattern of increased cross-country ability are designed for off-road conditions and on soft soils.
Winter (Z) is designed to work on snowy and icy roads, the gripping qualities of the surface of which can vary, depending on the situation, from minimal (smooth ice or porridge of snow and water) to small (packed snow in cold weather). The tread pattern of such tires has clearly defined "checkers" from the longitudinal and transverse grooves of considerable depth. The "checkers" have a complex figured relief to increase the working side surfaces, as well as a branched micro-pattern. Winter tires also denoted by the index M+S. Often they have a strictly defined direction of movement (indicated by an arrow).
Career (Kar) - for work in quarries, logging, etc. (for rocky and stony soils).
Also, the tread pattern is divided into:
- directional - not symmetrical with respect to the radial plane of the wheel; tires with a directional tread pattern are designed for use in off-road conditions and on soft soils;
- asymmetrical pattern tread - not symmetrical about the central plane of rotation of the wheel.
According to climatic version tires are divided into:
Tires for temperate climate used at temperatures not lower than -45 degrees C;
- frost-resistant tires designed for operation in areas with temperatures below -45 degrees C;
- tires for tropical climates, made from materials that can withstand moisture and high temperatures.
None of the inventions made by people contributed to such a technological breakthrough as the invention of the wheel. It made it possible to build vehicles on which it was possible, with relative comfort, to move and transport goods. But the tire itself, in the form in which we see it today, did not appear immediately. It took a long time before the wooden wheel turned into a high-tech tire. To do this, it was necessary to invent the vulcanization of rubber, solve the problem with the pneumatic tire, and only then talk about the elastic wheel. Today, all types of vehicles are equipped with such a wheel, from a bicycle to heavy lifting machines. Do not do without such a wheel and modern aviation.
If you look into the past, into history, it becomes clear that the main purpose of this invention was the desire to protect the vehicle from bumps and bumps while driving. After all, the lack of modern pavement and shock absorbers in the 19th century made traveling a dangerous occupation for health. Therefore, such an invention changed the very view of the transportation of people and goods, reduced distances and made humanity more communicative. Since then, the basic idea has not changed fundamentally, but, depending on the conditions of use, tires have some characteristics. That allows you to talk about their diversity.
The principle of operation is the same for all tires, when the torus-shaped shell rotates around an axis. It consists of several layers of cord fabrics covered with rubber using a special technology. To avoid deformation, these layers are protected. The front part is protected by a protector, and on the side, the sidewall protects the entire structure from impacts. The problem of fastening the tire to the rim, or, in today's terminology, to the disk, is solved by the presence of beads on the lower edge. The sides are rigid, do not stretch or deform due to the presence of wire rings inside. The inner surface of the tire is airtight, it is thanks to this that it is possible to create a pressure inside the tire that is higher than atmospheric pressure. After all, such a pressure difference is the principle of operation of elastic, pneumatic tire. fills up inner part under pressure, usually with air, but filling with gas, in particular nitrogen, is popular today. By the way, the very word pneumatic tire means air.
Today there are two types of tires - tube and tubeless.
Fig.1 Tube tire construction: 1 - rim; 2 - riding camera; 3 - tire; 4 - valve.
Fig.21 - protector; 2 - sealing layer; 3 - frame; 4 - valve 5 - rim.
All modern classification tires based on location layers of cord fabric. In the first option, these layers cover the entire tire and wrap around bead rings, forming frame. Another type is the arrangement of layers (breakers), directly, under protector, that is, in the place of the main contact with the road surface. Based on this, we can say that all tires produced today are divided into two main types: diagonal And vertical. Moreover, radial tires are the most popular.
Rice. 3 The construction of both types of tires ( A) diagonal, ( b) radial: 1 - board; 2 - bead ring; 3 - frame; 4 - breaker; 5 - side wall; 6 - protector.
The basis of the design of diagonal tires is such a mutual arrangement of the carcass and breaker layers when they intersect with each other at a given angle of 45 to 60 degrees relative to the line of rotation of the wheel. Whereas this angle in radial tires is 90 degrees.
The following figure clearly shows the main elements and their cross-sectional dimensions.
Fig.4. Tire design elements and their dimensions: 1 - frame; 2 - breaker; 3 - protector; 4 - sidewall; 5 - board; 6 - bead ring; 7 - cord filler.
Where D- outer diameter, H- profile height, B- profile width, d- tire rim diameter.
Commonly used name tire, implies a rubber-cord shell, a toroidal shape of a pneumatic tire, on which the main load from contact with the road surface falls. The often encountered names of tires, slope, rubber, balloon, are unacceptable and illiterate.
Applicable camera, in the tube version of the tire, with a valve serves to maintain a constant air pressure inside the structure.
Under the term tire carcass, understand a rubberized cord attached to the side ring, which takes on all the forces that arise when driving on the road.
concept breaker includes that part of the tire that is located between the tread and the carcass and consists of alternating layers of cord and rubber.
Tread- this is the part of the tire, which is located directly at the point of contact with the road surface, it is quite massive and is designed to protect the carcass and breaker from impacts. For better grip on the road, there is a pattern on the tread.
shoulder area on the tread - this is the area between the treadmill and the sidewall; it serves to protect the side area from damage.
Under the term board imply a detail of the tire structure with the help of which the fixation on the disk takes place. This part is rigid, with the presence of iron rings made of twisted, steel wire inside.
Side wall, located between the bead and the shoulder area of the tread, consists of several carcass layers. Outside, this part of the structure is protected by a sidewall.
Valve, regardless of whether it is located in the chamber or is part of tubeless rubber, is a valve through which air is pumped in or vice versa serves to bleed it.
Tire outer diameter, denoted by the letter D, is the height of the outer circle that is in direct contact with the road.
Bore diameter d- this is the line of intersection of the base of the bead with its outer surface.
Profile height, marked with the letter H- this is half the difference between the outer and landing diameters.
Profile width, which is usually denoted by the letter B, is the distance between the sidewalls, or rather, their outer parts. Excluding projections, inscriptions and other markings applied to the sidewall of the tire.
Today, tires are classified according to such a parameter as the ratio of the height and width of the profile in percent. This is a characteristic of this product according to the section profile.
The proposed designations are the minimum knowledge necessary for the owners of their own transport. But do not forget that the tire is not an independent technical unit and can only be considered as an integral part of a vehicle. Of course, it is an important part of it, on which the safety of operation of this vehicle and the comfort of the passengers in it depend. The right choice of tires can have a direct impact on such indicators as cross-country ability, smoothness, and vehicle economy. The noise level in the cabin is also important, which not least depends on the choice of tires.
Today, our roads are dominated by traffic foreign production, and in many cases domestic cars used in tire equipment foreign manufacturers. Domestic factories, specializing in the production of tires, have recently also begun to produce high-quality products that can satisfy any customer. For this reason, it is very important to navigate all this abundance. Knowing the intricacies of the products sold will allow you to make the right choice. Save money and at the same time purchase a quality product that significantly increases road safety.
When buying tires, first of all, you need to decide on their category, that is, on which car or trailer the goods are purchased. It is equally important to decide on the season during which these tires will be used. It is also important to know what form the profile needs to be purchased. This refers to the ratio of H / B parameters, which allows you to choose rubber low profile, wide profile or even with upper low profile.
In addition, tires can chamber And tubeless. Knowing all these parameters, you can easily choose exactly the products that are ideal for a particular vehicle.
On the car is very important. To do it right, you need to know the car tire device. If you properly shoe your " iron horse”, then he will ride briskly. So let's look at the tire inside and out.
Before part of the air from the tire is bled. Because of this, the area of the contact zone of the tread pattern increases (expands). As a result, the side pattern "slides" down and becomes part of the main tread. In extreme circles, they say that the tire “flattens”, changes its shape. And the more flattened the tire, the better it is for overcoming off-road.
- Landing collar - a circular thickening that runs along the inner diameter. The side "refuels" under the curvature of the edge of the disk. Such a device of the car tire allows you to fix the tire well on the wheel disk.
The structure of the tire in the context
Now consider the layered structure of the car ramp.
- The carcass of the tire is made on a fabric basis. It is made from a special rubberized cord thread. Thread layers alternate with layers of rubber, which are called squeegee.
For the cord, several types of polymer fibers (dacron or kapron) can be used as the base material. In the production of a tire carcass, a metal cord can also be used. It is made of steel thread, topped with a layer of brass. It is from the frame that the reliability, strength and durability of the design of the entire tire depends. Such characteristics are provided to the tire due to the structural features of the cord itself and the layers that border it.
The threads are separated by the rubber layer of their coating. At the same time, the fibers and cords are interconnected due to the close fit between them. And the squeegee layer protects the cord from moisture and prevents the metal threads from fraying. In addition, the rubber part of the carcass provides strength as well as elasticity to the entire tire.
Depending on the direction of the cord threads, there are two types of tires: radial and diagonal.
The device of a car tire with threads directed radially is the most common. In such tires, the cord threads are arranged radially, that is, parallel to each other. Due to this arrangement, minimal interaction of the layers and fibers of the cord is ensured. Due to this, the voltage level of the cord directed radially is several times less. Therefore, the thickness of the cord layer and the entire frame in the radial type slope is less.
Skates with a diagonal direction of the threads are characterized by a different construction of the frame layer. In it, the cord threads overlap at an angle of a certain degree. Bias tire always made of a pair of layers of cord. Its threads are located at an angle of about 50 degrees.
- Breaker- a separating layer that is located between the tire carcass and its tread. Consists of several cord layers. In each of them, the threads do not intersect and are located at a certain distance. Thick layers of rubber lie between the cord layers. The material for the cord is most often steel wire.
This structure and alternation of layers allows the breaker to be elastic and easily change its shape. When pressing on it, the surface bends due to the relative movement of the cord threads. And high elasticity is provided by rubber layers and partially by the elasticity of the steel cord.
The device of a car tire without a breaker is impossible. It is an intermediate link between a rigid carcass and a soft tread. Therefore, it partly enhances the softness of the outer layer, but at the same time weakens the excessive rigidity of the inner core of the tire.
Thanks to the breaker, the ramp can withstand mechanical shocks high power that fall on the tread surface. Due to the cord located under it, the energy from a wheel strike is distributed evenly over the entire surface of the tire and is quickly extinguished.
- The tread is a thick layer of rubber material with a tread pattern placed on it.
The first samples of ramps for cars were made from natural rubber. Then it was completely replaced with artificial rubber. Today, the composition of the rubber material, many manufacturers car tires kept secret from competitors. But basically it is a mixture of synthetic rubber and natural rubber with the addition of various ingredients that affect physical properties rubber.
Tubeless tires
The device of which is very different from the chamber type, are a separate class automotive rubber. In them, air is pumped into the cavity formed between the inner surface of the slope and the disk. The surface of the tire from the inside is provided with an additional insulating layer. It is made up of finely porous rubber high level gas tightness. IN modern models tubeless, this layer also has high astringent properties. Due to this, the puncture hole does not remain open, but is “knitted” (closed) with a special substance of this layer. The resource of walking a tire with such a “patch” is several hundred kilometers. In addition, such a layer increases the safety of the car on such rubber.
In tube-type rubber, with a large puncture, air will exit the hole quickly, and tire pressure will drop rapidly. Due to the high pressure difference between the wheels when moving, the car will roll towards the punctured tire. In tubeless air etching and sharp drop pressure through the puncture hole is blocked by tightening the hole with a binder.
Summing up
Now you know the car tire device. Although this information is only basic, it will help you when buying "slippers" for your car.
