Tires: Application and ID

TIRE IDENTIFICATION










Tire type, size, aspect ratio and speed rating are encoded in the letters and numbers imprinted on the sidewall of the tire (e.g. P295/40R20 101V) and (P225/45R17 84V). Refer to the chart to decipher the tire identification code.
Performance tires have a speed rating letter after the aspect ratio number. For example, the letter H indicates that the tire is speed rated for continuous speeds of up to 130 mph (210 km/h). The letter V indicates that the tire is speed rated for continuous speeds of up to 149 mph (240 km/h). The speed rating is not always printed on the tire sidewall.
- Q up to 100 mph (160 km/h)
- T up to 118 mph (190 km/h)
- U up to 124 mph (200 km/h)
- H up to 130 mph (210 km/h)
- V up to 149 mph (240 km/h)
- Z more than 149 mph (240 km/h) (consult the tire manufacturer for the specific speed rating)

The 20 or 17 on the sidewall is the tire bead/wheel rim diameter in inches.



TIRE RATING







The tread wear/traction/heat (temperature) resistance ratings are also imprinted on the tire sidewall(e.g., 250 AB).
The tread wear rating is expressed as a 3-digit number. It is a comparative value based on the wear rate of a tire when tested under controlled conditions. The test is done on a U.S. Government designated test course. For example, a tire with a tread wear rating of 300 should have a 50 percent better tread life than a tire with a 150 rating. In reality, the tread wear performance of the various tires greatly depends upon:
- The driving habits of the owner
- The actual driving conditions
- Tire service attention
- Climate
- Road surface temperature
- The road/street surfaces that the tires encounter
The tire traction and the heat (temperature) resistance ratings follow the tread wear rating. They are encoded either A, B or C. An A code represents the best rating in either category.
The traction ratings are based upon a tires ability to stop a vehicle on wet pavement when tested under controlled conditions on U.S. Government designated asphalt and concrete test surfaces. The traction rating assigned to a specific tire is based on straight-ahead braking traction tests and does not include cornering/turning traction.
The heat rating represents a tire's resistance to temperature increases from friction and its ability to dissipate heat. This test is done under controlled conditions on a specified indoor laboratory test wheel. Sustained high temperature can cause the construction material of a tire to degenerate. This will greatly reduce the life of the tire. A C rating represents the minimum acceptable heat resistance performance for a tire.

NOTE: The heat resistance rating is based on the tire being properly inflated and not overloaded. Excessive speed, under-inflation and/or excessive load can cause the temperature of a tire to increase above normal. This excessive heat may cause tire failure.