How to upgrade and modify tires The most important principle of tire upgrading.

The main principles of how to upgrade tires are as follows: 1) Quality upgrade The quality of tires has many evaluation indexes such as temperature grade, grip grade and speed grade. Tire quality upgrade refers to using the same tires as those from tyre size, but replacing them with high-grade tires. By improving the quality, you can get more beautiful tread patterns, better drainage performance, less rolling noise, or better driving stability. What do you mean by temperature grade, grip grade and speed grade? -Temperature grade refers to the tolerance of the tire to the heat expressed by the tire when the test is carried out on the test wheel in the designated indoor laboratory under standard conditions. Continuous high temperature will lead to tire material aging and shorten tire life. Too high a temperature will cause the tire to spiral. There are three temperature levels: A-B vest, B- medium and C- normal. -Holding level refers to the test site under standard conditions designated by the US government, which shows the straight braking performance on wet asphalt pavement and cement pavement, excluding turning performance. Levels include three general levels: A, B, Intermediate and C.. The speed level indicates the highest speed of the tire when it bears the specified load under the specified conditions. It is represented by the letters A ~ Z. 2) Specification upgrade The tire size upgrade is mainly to improve the driving stability of the tire and make the appearance of the vehicle more fashionable by replacing the wide-section tire within the scope permitted by the body chassis structure. Usually, the specifications and quality of tires will be upgraded. Tire size upgrade is usually accompanied by rim upgrade. The main principle of tire standard upgrade is basically not to change the tire outer diameter, but to increase the tire inner diameter and expand the tread. When upgrading, the difference between the total diameter (outer diameter) of the upgraded tire and the diameter (outer diameter) of the original tire must be within 3%. When the tire is upgraded, it needs accurate calculation to make the tire diameter almost unchanged. Let's take 185/60R 14 as an example. The rim diameter is 14in(355.6mm), and the sidewall height is1850.6 =11mm. Because there are sidewall heights above and below the rim, the total sidewall height is112 = 222 mm. The tire diameter is 355.6222 = 577.6mm ... If the 195/50R 15 tire is to be replaced, There are the following parameters: rim diameter 15in(38 1mm), sidewall height1950.5 = 97.5mm. Because there are sidewall heights above and below the rim, the total sidewall height is 97.52 = 195mm. The tire diameter is 38 1( 195=576 mm). Compared with the tire with the specification of 185/60R 14, the tire with the specification of 195/50R 15 has a diameter difference of 577.6-576= 1.6 (mm) and a diameter difference ratio of/kloc. If you want to widen the tread, but don't want to change the tire length-width ratio, that is, choose 195/60R 14 standard tire, you will have the following parameters: rim diameter 14in(355.6mm), sidewall height1950.6 =/kloc-0. Because there are sidewall heights above and below the rim, the total sidewall height is 1 172=234 mm, and the tire diameter is 355.6234 = 589.6 mm. The tire with specifications of 185/60R 14 and the tire with specifications of14. The diameter of the tire varies greatly. After the tire is upgraded, it is necessary to check whether there is friction or collision between the tire and the wheel liner, and consider the buffering coefficient of the shock absorber. As can be seen from the above calculation, tire upgrading usually follows the principle of not changing or only changing the outer diameter of small wheels. For example, the tyre size of FAW-Volkswagen Jetta Pioneer Factory is 185/60R 14, and the tires with specifications of 195/50R 15 can be replaced; Guangzhou Accord and Shanghai Volkswagen Passat are equipped with tires with specifications of 195/65R 15, and the tires with specifications of 205/55R 16 can be replaced.