How to Read Tires
Tires are stamped with traction, temperature and resistance-to-wear grade and ratings to help you purchase the right replacement tires for your vehicle and assist in choosing a tire that will meet your driving needs. Your vehicle’s tires should all be the same size and grades (the exception being some performance cars that utilize front tires with a different size than the rear tires).
Tread wear, Traction and Temperature Grades: Tread wear indicates an estimate of how long the tire tread will last before the tire is worn out. Grading starts at 100 and goes up to 500, with 500 being the longest lasting tire wear grade. Tire wear also is determined by tire maintenance, your driving style and where you drive. The word “Traction” followed by a letter A, B or C (A providing the best traction) rates the tire’s ability to stop on a wet road surface. Most quality tires will indicate an “A” grade. “Temperature” grades the tire’s ability to withstand and dissipate heat. It also is graded A, B, or C, where “C” indicates a temperature grade that meets Federal requirements for passenger car tires, and A and B providing an even higher level of performance. This can be very critical if you live in a hot climate where road temperatures can increase tire temperature significantly.
DOT Number: This indicates compliance with the Department of Transportation safety standards. The “DOT” will be followed by the tire’s identification number, which is used to identify a variety of characteristics about that tire including the manufacturer and plant code, tire size code, optional codes and the date the tire was tire is recalled. For example, 059 indicates a tire that was manufactured in the 5th week of 1999.
Size: This designates the size of the tire, such as a 15 inch or 16 inch tire. Below is a breakdown of a typical tire size and tire ratings that are located on the sidewall of the tire, and what the numbers and letters indicate.
|P||“P” indicates passenger cars. You also may see “LT” for light truck and “T” for temporary spare.|
|205||The nominal width of the tire in millimeters.|
|70||Indicates the relationship of the tire sidewall height to the width of the tire.|
|R||Indicates a radial belted tire. You also may see “B” for belted bias and “D” for diagonal bias.|
|15||The wheel (rim) diameter in inches that is required for this tire. The most common are between 12 and 18 inches.|
|95||Load index. On passenger cars and light trucks, the load index may range from 65 to 150.|
|T||Speed rating, which ranges from A through Z (with A being the lowest rating).|
To determine which tire size is recommended for your vehicle, check the tire sticker that can be found in one of the following locations: vehicle door edge, door post, glove box door, or fuel door.
Load Index/Load Rating: The load index is a number ranging from 0 to 279 indicating the maximum load a tire can carry at the speed indicated by the speed rating.
Speed Index/Speed Rating: The speed rating is an alphabetical code (A through Z) indicating the range of speeds at which the tire can carry a load corresponding to its load index. When replacing your tires, consult your vehicle owner’s manual for the tire’s recommended speed rating.