How to determine the size of automobile wheels

There are many kinds of classification: classification by vehicle type, classification by use, classification by size, classification by mode and classification by structure.

Classification by car type

According to the vehicle type, tires can be divided into eight types. Namely: PC- automobile tire; Lt- light truck tires; T B- truck and bus tires; Agricultural vehicle tires; Construction vehicle tires; Id- industrial vehicle tires; AC- aircraft tires; MC- motorcycle tires.

Classification by tire use

Tires are classified by use, including truck tires, passenger car tires and mine tires. Truck tires must be marked with the number of layers in addition to the specifications and dimensions on the tire wall. But what I need to tell you here is that the number of layers of truck tires does not refer to the actual number of layers, but refers to the tires made of high-strength material cords, and their load-bearing performance is equivalent to that of tire cords made of cotton cords. This is because cotton cord was first used to make carcass cord. Therefore, it is an international practice to express tire layers based on the number of cotton cord layers. Different grades of tires have different bearing capacity. Even tires of the same specification have different bearing capacity due to different grades. Therefore, different grades of tires cannot be used on the same axle, otherwise it will be very dangerous when driving at high speed and loading. For example, 900-20 tires of Jiefang vehicles (16 grade) cannot be used on the same axle as 900-20 tires (14 grade), because they have different grades and different loads, and are prone to danger after mixing.

Light radial tires of light trucks or trucks should be distinguished from radial tires of cars by adding the letter "C" after the tire model. For example, the tire of Jinbei van is 185SR 14C, where "c" indicates that this tire is a light truck tire. American Standard stipulates that passenger car tires should be indicated by the letter "P" before the tire size. For example, P2 15/75R 15 tire for Cherokee, where "P" indicates that the tire is a passenger car tire. Many drivers don't understand the meaning of the word "P" and blindly think that American cars must use tires with the word "P". Therefore, tires without the word "P" are afraid to be used when changing tires, and often make some jokes. Some tire dealers sell tires with the word "P" at high prices after meeting drivers with this mentality. In fact, the word "P" is only a regulation of the United States. For example, if the tire 185/70R 14 produced by Shanghai Warrior Tire Factory in China is to be exported to the United States to be used together with the Tianba car produced by Ford Factory, then according to American regulations, the tire 185/70R 14 produced by Shanghai Warrior Tire Factory must be added in front. Therefore, don't be fooled by the word "P" when changing tires. On the contrary, this "c" word. You should pay attention that if your car is a light truck, you must insist on not changing the tires without a "C". As mentioned above, the Jinbei van uses 185SR 14C radial tires, and Audi cars also use 185SR 14C radial tires. From the perspective of tyre size, there is no difference, just because there is a "C" on the tire of Jinbei van. Therefore, their air pressure and load are very different. Once a light truck is replaced with a tire without the word "C", it is necessary to measure whether the tire can bear the weight of the car and the expected cargo to be carried. If the ultimate load of the tire is less than the weight of the car and the quality of the goods it carries, it must not be used, or attention should be paid when carrying passengers or goods. Otherwise, it's like putting four untimely bombs in your car. I don't know when the load exceeds the limit of the tire, and when the speed reaches a certain level, vicious accidents such as tire puncture and rollover will occur. Therefore, please pay special attention to drivers and friends. If your car needs tires with the word "C", you'd better not let the word "C" disappear.

In addition, light truck tires are sometimes indicated by "LT" before or after the tire model. For example, LT 2 15/75R 15, 145R 12LT (Shandong Triangle Brand) and other tires, where "LT" also indicates that this tire is a light truck tire. Here, I would like to remind drivers in particular that this is also a situation that I often encounter in my work: drivers of some vans and passenger-loan double-row minivans often change the bias tires into radial vacuum tires for comfort and safety. Judging from bias tires and radial vacuum tires alone, vacuum tires are undoubtedly much safer, but you must consider whether your car is loaded or not. If it is loaded, it must be changed to the one with "C". In addition, we should also understand the interchangeability between radial tires and bias tires, that is to say, if you want to change the bias tires of the original car into radial tires, please don't change them indiscriminately, otherwise it will affect the performance of the car.

The following is the interchange table of bias tire and radial tire. Please refer to this table for interchange. This table only refers to the interchangeability of tire sizes, and does not consider safety factors such as load and speed, nor does it consider the collision between tires and body, fender and other parts. Please actually check and make sure there is no problem before replacing it.

Interchange platform for bias tire and radial tire

Radial tire with bias tire

(Offset) 80 Series 70 Series 65 Series 60 Series

4.50— 12 135 r 12 155/70r 12 145/65r 13 16560 r 13

5.00— 12 145 r 12 165/70r 12 175/60r 12 175/60r 12

6.00— 12 12 12 175/70r 12 165/65r 13 185/60r 13

5.20— 13 135 r 13 155/70r 13 165/65r 13 185/60r 13

5.50— 13 145 r 13 165/70r 13 175/65r 13 185/60r 13

5.60— 13 15 13 175/70r 13 185/65r 13 185/60r 13

6.00— 13 165r 13 185/70r 13 185/65r 14 195/60r 14

6.50— 13 175r 13 185/70r 14 195/65r 14 205/60r 14

5.20— 14 145 r 14 165/70r 14 185/65r 14 195/60r 14

5.60— 14 15 14 175/70r 14 185/65r 14 205/60r 14

6.00— 14 16 5r 14 185/70r 14 205/65r 14 225/60r 14

6.50— 14 175r 14

7.00— 14 185 r 14

7.50— 14 195 r 14

8.00— 14 206R 14

5.60— 15 155r 15

6.40— 15 175r 15

Classification by tire size

Tires are classified by size, generally referring to tires with cross-sectional width of 17in (inches, 1in = 25.4 mm), which belong to giant tires. A tire with a cross-sectional width of 17 inch or more is a large tire. Tires with a cross-sectional width of 10 inch are small and medium-sized tires.

Tire pattern classification

There are many types of tires classified according to patterns, but they can generally be divided into five types:

① Straight groove pattern, also called ordinary pattern. This pattern has excellent handling stability, low rotation resistance, low noise, especially excellent drainage performance, and is not easy to slip. The reason why it is called ordinary pattern is relative to cross-country pattern and mud snow pattern. In fact, generally speaking, there are many kinds of common patterns, because every big tire manufacturer has its own laboratory and tire testing ground, where countless engineers and technicians study patterns. However, in the process of research, different people have different views. Some patterns pay attention to tranquility and comfort, some patterns pay attention to waterproof and anti-slip, some patterns pay attention to grip, and some patterns pay attention to low fluctuation resistance and fuel economy. Therefore, although it is only a narrow tread, there are thousands of changes, which can really be described as "a world of flowers and flowers between square inches." Moreover, major manufacturers are constantly introducing new tricks every year.

② Transverse groove pattern. The driving force, braking force and traction of the transverse groove pattern are particularly excellent, and its wear resistance is also excellent. Therefore, it is very suitable for bulldozers, excavators and other construction vehicles, but the mobility and drainage performance of the transverse groove pattern are poor.

③ Vertical and horizontal grooves. Vertical and horizontal grooves are also called comprehensive grooves, which have the advantages of vertical and horizontal grooves. Therefore, it is also suitable for off-road vehicles such as jeeps, such as 750- 16 tires used by Japan's Sanling Jeep Factory.

④ Mud and snow patterns. Mud and snow patterns, as the name implies, refer to patterns specially designed for use in mud and snow. It is represented by the letter "M+S", where "m" refers to mud and "s" refers to snow. Generally, the sidewall of this kind of tire is directly engraved with "M"+"S" rust, and people with "M"+"S" can see it at a glance. In foreign countries, such as Japan, most drivers have snow tires or use snow chains for driving safety in snowy days. After winter, some people who don't want to keep them until next year will sell them. At present, many people in our country are dealing in this kind of tires, and the specifications are mostly for mini-cars. They named this kind of tire "Landing New", which means that it has landed, but it is still very new. I would like to remind users that when using this kind of tire, the anti-skid nails on the tread must be removed, otherwise the road surface will be damaged, because many of our drivers don't buy this kind of tire for snow angels.

It is a waste to sell snow tires for a winter, but it occupies a lot of land and is troublesome to raise. In order to solve the problem that snow tires can't be used in summer, Japanese BS company has studied several patterns that can be changed. This pattern will change with tire wear. First of all, since the winter, snow patterns have played an excellent role in stepping on snow. After winter, the shoulder groove specially designed for snow has worn out, showing the performance of ordinary patterns. This dual-purpose tire solves the problem of using tires in snow angels and will not be wasted; It can be described as well-intentioned. At the same time, it also reflects the professionalism of Japanese businessmen.

Four basic tread patterns and their characteristics: longitudinal tread pattern, transverse tread pattern, longitudinal tread pattern and block tread pattern;

① Longitudinal groove tread = excellent handling stability/low rotation resistance/good drainage/not easy to slip.

② Transverse groove tread = excellent driving force, braking force, traction/wear resistance.

③ Vertical and horizontal tread patterns = the advantages of both vertical and horizontal tread patterns.

(4) Block tread = good driving force and braking force.

5 off-road mode. Cross-country mode is designed to adapt to dry, wet, rugged mountain roads and muddy and sandy roads. Just like a pentathlon athlete, this tread tire has several advantages and can be used in various harsh environments and climates. Therefore, it is the best tire for young people or off-road vehicles such as jeeps. Off-road tires, in addition to enjoying the pattern codes of various factories, generally have a very touching name. Such as Japanese Toyo tire MG 10 1 pattern. Because this pattern is very suitable for windy, dry, wet and rugged mountain roads, the factory gave it an ironic and beautiful symbol name-"Normandy Landing", which took the meaning of the Normandy landing campaign commanded by Eisenhower, a five-star American general during World War II (Normandy landing was won by other factors, but the tires used by the allied forces were unimpeded on the beaches and mountain roads at that time, which was also an important reason for the allied forces to win. From the name given to it, you can imagine the excellent off-road performance of this model.

Tires can be divided into the above five categories according to the pattern, so when you know what pattern tires are used in your car, you can go to the tire shop to buy the tires you want.

In addition, some tires have directional patterns, mainly considering the grip performance. When installing such tires, attention should be paid to marking the installation position according to the rolling direction. If there is no mark on the tire, the tip of the pattern will touch the ground first. However, if this kind of directional tread tire is used on an off-road vehicle with equal front and rear wheel pitches, the two tires on the front wheel can also be reversed. After reverse installation, if your car runs on a muddy road, the front wheel becomes shallow, reducing rolling resistance and saving fuel. At the same time, after the front wheel rolls over, the road surface is slightly compacted, which is beneficial for the rear wheel to pass and improve the traction. This is the experience summed up at work, which is not required by tire manufacturers, but you might as well try it, and the effect will be very good.

Classification by tire structure

According to the structure classification and the current widely used situation, tires can be divided into two categories: bias tires and radial tires.

At present, bias tires are widely used in trucks and freight cars in China. For example, the 650- 16- 10 tires used in Beijing104/car, and the 750- 14-8 tires used in Beilv van are bias tires. Radial tires are mostly used in automobiles. For example, the 185/70R 13 tire used in Santana car produced by Shanghai Volkswagen Automobile Factory, the P2 15/75R 15 tire used in Beijing Cherokee, and the175r15 tire used in FAW Jetta car.

Radial tire has been widely used in western Europe and other developed countries.

The influence of tires on cars is very huge and direct.

Start with a novel:

Usually refers to the big generally divided into tire diameter and landing area.

Large tire diameter:

Can give the car better passability, if the engine horsepower is large enough,

It can also improve the top speed of the car to a certain extent. Moreover, as the tire diameter becomes larger, the height of the automobile chassis from the ground increases accordingly, which makes the automobile have better passability on rugged mountain roads. However, the increase in tire weight also increases the fuel consumption of the car. It will also reduce the stability of the car because the chassis is too high from the ground. Therefore, when the car is equipped with large tires, the distance between two parallel tires will increase.

If the tire has a large landing area:

It can give the car more friction, make the car more stable, make the dry road not easy to slip, and improve the braking performance. The bad effect is to increase fuel consumption and tire noise during exercise.

Small tires have an opposite effect on vehicles.