What Do the Numbers on Tires Mean?
2 Answers
Tire model such as: 225/60-R17-99H, 225 represents the section width, simply understood as the width of the tire tread. 60 represents the aspect ratio, simply understood as the height of the tire sidewall. R represents the tire type code, where R stands for radial tire. 17 represents the rim diameter, indicating that the tire is suitable for 17-inch rims. 99 represents the load index of the tire, which is the maximum weight the tire can bear. A load index of 99 means the tire can bear a maximum weight of 775KG. H represents the speed rating of the tire, which is the maximum speed the tire can handle. A speed rating of H means the tire can handle speeds up to 210KM/H. Additional information: 1. Tire specifications: Car tire specifications are commonly represented by a set of numbers, where the first number indicates the tire section width, and the second indicates the rim diameter, in inches. 2. For example, 210/50R18 means a tire width of 210 millimeters, an aspect ratio of 50, and a rim diameter of 18 inches. The letters or symbols in the middle have special meanings: "X" indicates a high-pressure tire; "R" and "Z" indicate radial tires; "-" indicates a low-pressure tire.
As an experienced driver who often helps friends check their cars, I've found that the numbers on the side of the tire, such as 205/55 R16 91V, are quite important. 205 is the tire width in millimeters, 55 represents the height as a percentage of the width, known as the aspect ratio—the lower the number, the thinner the sidewall, which improves handling but increases bumpiness; R stands for radial construction, 16 is the wheel diameter in inches, 91 is the load index corresponding to 615 kilograms, and V is the speed rating, allowing speeds up to 240 kilometers per hour. Don’t underestimate these details—choosing the wrong size can lead to vehicle instability or increased fuel consumption. I recommend regularly checking tire pressure and keeping it within the range specified in the manual, usually between 2.3 to 2.5 bar, which can extend tire life by thousands of kilometers. When replacing tires, always match the original factory numbers, otherwise the wheels won’t fit, and driving at high speeds becomes even more dangerous. I’ve seen many accidents caused by misreading these numbers, so I always remind car owners to carefully check the manual when changing tires.
