If you have been out looking at all the tires on sale, you have probably seen the Uniform Tire Quality Grade (UTQG) on labels affixed to tires, referenced by online tire retailers, on the sidewalls of your current tires, or in brochures at tire stores. The ratings are required by US law for most passenger cars, but not for light truck tires or specialty tires like spare or snow tires. The ratings are designed to aid consumers in comparing tires and making buying decisions. Understanding the UTQG ratings can help you set your expectations and choose the right tires. Our guide to the Uniform Tire Quality Grade ratings is below.
UTQG ratings consist of grades in three areas: treadwear, traction and temperature resistance. You should understand that the tests are conducted by the tire manufacturer or an outside firm hired by the manufacturer to do the testing. The National Highway Traffic Safety Administration (NHTSA) does not conduct or oversee the actual testing, but the NHTSA can review a tire company's data and levy fines if discrepancies are discovered. You should also take into account that the tests are conducted under standard testing conditions. This means that they do not account for things you may encounter like over or under inflation, poor alignment or overloading so the actual performance of your tires may deviate.
Treadwear Grades
The treadwear grade is based on actual road use. The number is arrived at by comparing the treadwear of the tire being tested to that of a control tire. So a tire with a treadwear grade of 200 would last two times as long as a tire graded at 100. The Uniform Tire Quality Grade treadwear test is run for just 7,200 miles, so there is a lot of wiggle room for tire manufacturers to extrapolate and project tread life. This makes it difficult to compare treadwear grades from one manufacturer to another as different companies have different philosophies about this grade. Some tire manufacturers see the treadwear grade as a selling point and thus may be slightly optimistic with their projections while others may be more conservative with theirs. It may be helpful to look at both the treadwear grade and the treadwear warranty offered if one is available to get a better sense of what you might be able to expect.
Traction Grades
The traction grade is based on a straight line braking test conducted on a wet test surface. Cornering and turning, dry braking or resistance to hydroplaning are not tested nor reflected at all in this rating. Grades used are AA, A, B, and C with AA being the highest rating assigned.
Temperature Resistance Grades
Temperature ratings represent the ability of a tire to resist generating and dissipate heat. Tires that cannot dissipate or resist heat are unable to perform at high speeds, have reduced tire life and are subject to sudden failure. The temperature ratings from high to low are A, B and C. Tires sold in the US must earn at least a C rating. A tire with a C rating has been proven to withstand speeds of 85 to 100 miles per hour. A rating of B indicates the ability to perform between 100 and 115 mph while an A rating indicates that the tire was able to perform at 115 mph during testing without failing.
Now that you understand the Uniform Tire Quality Grading system, you might not be fully convinced that these ratings meet their goal of providing clear information to help consumers evaluate tires. While UTQG ratings can be helpful, there are many other factors to consider such as your driving habits, your environment and your budget.