The second half of the service description is known as the speed rating. Devised to give the buyer an awareness of the tire capability for safe operating speed, it's the W in our 98W service description. As you can see the tires on our new Mustang are rated safe to 168 mph. Three of the most common speed ratings are S, H, and V. The complete speed-rating table is as follows.
From our service description we know that a set of our P235/55/R17 98W tires will carry a total load of 6,612 pounds at up to 168 mph safely. You should note that the speed rating doesn't apply to tires that are worn out, repaired, damaged, retreaded, or not properly inflated. Make sure your installation technician has paid attention to any unidirectional marking on the sidewall as required.
The uniform tire quality grading, or UTQG is another important source of information on the sidewall of the tire. In the UTOG, three graded categories include the areas of tread wear, traction, and temperature.