The tire is the most direct part of the vehicle in contact with the ground, and it is also the basis for ensuring the driving and braking of the vehicle. However, many car owners still have a primary level of understanding of tires, and they have been trapped several times without knowing it.

1. The function of the tire 1. Bearing function: bear the load of the vehicle.

2. Traction/braking function: transmit driving and braking force to the road.

3. Mobility stability: change and maintain the direction of the vehicle.

4, driving comfort: absorb the vibration from the ground.

2. Tire classification and structure Tire classification-according to structure: according to the different arrangement of carcass cord layers, there are radial structure and bias structure.

Tire construction:

Tire structure-component function: 1. Tread: The only part of the tire that contacts the ground requires wear resistance, traction, and rolling resistance characteristics.

2, steel belt layer: placed between the tread and the carcass to increase strength and strengthen the role of tread strength.

3, steel tire body cord fabric (carcass cord fabric): high strength, high fatigue resistance steel cord fabric, supporting the tire carcass part.

4. Airtight Layer Protective Rubber (BACK UP LINER): Carcass cord cloth wrapping cloth, rubber-like composition, to prevent the airtight layer rubber from penetrating into the part between the carcass cord cloth.

5. Airtight layer: to ensure that the tire inflation pressure is maintained and the inner part of the tire is wrapped.

6. Bead: The part in contact with the rim, the strongest in the tire structure, and the part that seals with the rim to support the vehicle.

Three, tire identification 1, specifications and technical parameters

① Tire outer diameter: It is the diameter of the tire when there is no load after the tire is installed on the corresponding rim and inflated according to the specified air pressure.

② Total tire width: refers to the maximum width of the tire including the text and pattern on the side of the tire (expressed in mm).

③ Applicable rim width: It is the rim width suitable for tire performance. Standard rim: the most suitable width and shape (expressed in). Applicable rims: rims that can be used.

④ Rim diameter: refers to the rim diameter of the wheel suitable for the tire, which is the same as the inner diameter of the tire (expressed by in).

⑤ Tire section width: the width of the text and pattern thickness on the side of the tire (expressed in mm) is removed from the total width of the tire.

⑥ Tire height: 1/2 of the number obtained by subtracting the rim diameter from the outer diameter of the tire.

⑦ Tread width: is the width of the tire tread. Refers to the width of the most prominent part of the two sides.

⑧ Tread radius: refers to the radius of curvature of the tread portion.

2. Sidewall

3. Load index

What is the Load Index (LI)?

The ability of a tire to bear the weight (maximum) is called the load capacity, and this load capacity expressed by the index is called the load index.

②Look at what part of the tire can be understood?

As shown in the figure below, there is a tire size representation on the side of the tire. LI is then indicated in the dimensions of the tire.

③ Correspondence between LI and load capacity

4. Speed level

5. Function of tire pattern

①Drainage effect; ②Improve maneuverability and stability; ③Increase the braking force, driving force and traction of tires; ④The heat dissipation effect of tires.

4. Basic characteristics of tires 1. Static: When an inflated tire is load-bearing, the tire will "bend". There are three types of such bending, which are longitudinal bending, side bending, and lateral bending, and are indispensable elements for tire function.

2. Dynamic:

The occurrence of tire rolling resistance is due to: ①Energy loss caused by repeated deformation of tire components; ②Resistance due to friction between the tire and the road; ③Air resistance of the tire.

3. Drainage performance: When driving at high speed on a road with water, because the grooves of the tire cannot drain the water on the road, the water film enters between the tread and the road, so that the tire floats from the road. As a result, the tire skids on the water, a condition called floatation.

4. Standing wave phenomenon: Although the tire is round, it does not use a line but a surface when contacting the road. Such deformation and restoration of the grip portion are also repeated during rotation. At the time of high-speed running, this deformation is not restored even after the grip is completed, and the vibration wave remains in the rear portion of the grip portion. This wave phenomenon is called "standing wave phenomenon".

5. Steering performance:

Tire side resistance/side stiffness:

The higher the rigidity of the tire (increased air pressure, increased rim width, radial structure, small flatness rate), the higher the lateral stiffness. However, if the air pressure and the rim width are not controlled within the allowable range, it is very dangerous.

Load increases, side resistance will increase. However, after exceeding the recommended load of the tire, the side resistance will gradually decrease.

When driving on a wet road surface, the friction force will decrease, so the side resistance will also decrease.

6. Noise:

Main sources: pump noise, pattern pitch noise, tread sidewall vibration, bell mouth effect.

1, the right pressure

Insufficient air pressure: cause the tire deformation to become larger, which will cause abnormal heat generation and increase the possibility of failure, and accelerate the abnormal wear of the ground contact surface.

Proper air pressure: The tire can have the best shape.

The air pressure is too high: the tire deformation is too small, the cushioning impact force is reduced, the riding comfort is not good, and the tire is prone to trauma, and the abnormal wear of the contact surface is accelerated.

2. Rotation: Different tire device positions have different wear methods and progress. Therefore, the tire positions must be exchanged regularly (about 5,000km per driving) (tire exchange).

Advantages: prevent partial wear, extend tire life, and make tire fatigue uniform.

Because the front wheel of the FF car is the driving wheel and steering wheel, it wears 2 to 3 times faster than the rear wheel, and the tire exchange must be carried out as soon as possible.

Partial wear: In the event of abnormal wear, it is necessary to judge from its state whether it is caused by too high or too low air pressure or improper positioning, and make necessary adjustments as soon as possible.

Wheel balance: In high-speed driving, even a small imbalance can cause vibration. Therefore, when the vibration is felt, the wheel balance should be adjusted as soon as possible.