What Do the Markings on Tires Mean?
3 Answers
Tire model numbers and letters explained: Taking 225/60-R17-99H as an example. 1. 225 represents the section width, which can be simply understood as the width of the tire tread. 2. 60 represents the aspect ratio, which is essentially the height of the tire sidewall. 3. R stands for the tire type code, with R indicating a radial tire. 4. 17 represents the rim diameter, meaning the tire is suitable for 17-inch rims. 5. 99 indicates the load index of the tire, which is the maximum weight the tire can bear. 6. H represents the speed rating of the tire, indicating the maximum speed the tire can handle.
That string of numbers and letters on the tire sidewall is actually its ID card. Last time I changed tires, I specifically researched it. For example, take the code 215/55R17: 215 indicates the tire width in millimeters, 55 is the aspect ratio (the sidewall height is 55% of the width), R stands for radial construction, and 17 corresponds to the wheel rim size in inches. The following 94V is even more critical—94 is the load index corresponding to a maximum load capacity of 670 kg, and V is the speed rating with a top speed of 240 km/h. There's also a small four-digit number in the corner, like 3221, indicating the tire was manufactured in the 32nd week of 2021. Inside the tread grooves, there are triangular wear indicators—once the tread wears down to those marks, the tire must be replaced, otherwise, wet traction will plummet dramatically.
Sharing a practical tip: Tire markings hide safety codes. My tire reads TREADWEAR 380 - higher numbers mean better wear resistance, but there's a world of difference between 300+ for regular tires and sub-200 for racing tires in terms of grip. TRACTION A indicates wet grip rating (AA being the highest), while TEMPERATURE A represents heat resistance. Pay special attention: winter tires feature a three-peak mountain snowflake symbol, while all-season tires carry the M+S (mud and snow) marking. Last week when checking my neighbor's tires, I noticed the last four digits of the DOT code were worn off, making it impossible to tell they were already six years old - aged rubber is dangerous regardless of tread depth.
