The inscriptions on the side of any tire carry full information about the tire. Knowing how to decipher these inscriptions, you can get all the characteristics of the rubber and find out if it fits a certain type of car or type of wheel. There are metric ways to indicate the size of the tire and the so-called English.
Instructions
Step 1
Inspect the tire sidewall carefully. Find an inscription on it like 165 / 70R13 (tires VAZ-2106). The numbers may differ depending on the dimension of the rubber, but, as a rule, the inscription has just such a representation. In this case, the first figure (165) means the width of the profile in millimeters. The second digit (70), indicated through the fraction sign /, means the height of the profile as a percentage of its width (from the first digit). The letter R stands for the type of tire (radial). The next number after the letter R shows the tire rim in inches. 1 inch = 25.4 mm. The rim diameter of the tire must be equal to the diameter of the rim
Step 2
The designation of bias tires, which were widespread until the early 80s of the last century, is 8, 10-15. In this case, the first number means the width of the profile in inches, and the second - the landing diameter of the tire, also in inches. The height of the profile is not indicated, but most often it is equal to 80% of its width. In addition, the same designation, translated into millimeters, is rarely found. For example, 205-380. The figures have been rounded to the nearest five or zero.
Step 3
The English tire sizing system is more common on tires designed for tuning SUVs, on ATV tires, on off-road trucks. It looks like 25x8-12 (tires for ATV). In this case, the first figure means the total diameter of the tire installed and inflated to the recommended pressure. The second number, always after the cross, indicates the total width of the profile. The third is the landing diameter, which should be equal to the diameter of the disc. On domestic trucks, all-terrain vehicles, tire sizes are also indicated, but instead of inches, millimeters are used. Occasionally, there is another indication of this size, for example 25x8R12. At the same time, the numbers retain their meaning.
Step 4
Tire size numbers may be preceded by the letters P or LT. The letter P indicates that the tire is intended for passenger cars, the letters LT for light trucks. In the US, light trucks also include SUVs, pickup trucks, and vans. The letter standing after the size at some distance means the tire speed index, that is, the maximum speed for which it is designed. In addition, on radial tires with metric size designation, the speed index is often indicated before the letter R.
