UTQG stands for Uniform Tire Quality Grading Standards. The U.S. Department of Transportation and the National Highway Traffic Safety Administration came up with them as a way to communicate useful information about a tire’s relative treadwear, traction, and temperature capabilities. By law, most passenger tires have to come with this rating, but it’s not required for many other types of tires: winter/snow tires, deep treaded light truck tires, trailer tires, spare tires, or tires under 12”.
It’s important to understand that these ratings are relative, and not set against a standard set by the U.S. DOT. In fact, the DOT doesn’t even conduct the testing. The tire manufacturers (or an independent testing company they hire) conduct the tests and assign ratings to their tires, so the standards are only relative to their own base standards, not all tires on the market. (The NHTSA does have the right to inspect the data and fine the manufacturers for inconsistencies, so they are held accountable for accuracy.) Below is a picture of what a UTQG rating looks like on the sidewall of a tire. We’ll use it as an example when discussing the individual ratings. So, what do these ratings mean, and how can they be useful to understand when purchasing your next set of tires?
The first portion of the rating is a 2 – or 3-digit number that represents relative treadwear, or how long the tire’s tread is expected to last against the standard test tire. The test track they use is a 400-mile loop for a total of 7,200 miles. If a tire is rated 100, it is expected to last as long as the test tire. A tire rated 200 will last twice as long, one rated 300 will last 3 times as long, and so on. Another example is that a tire rated 800 will likely last twice as long as a tire rated 400.
Because the test tires are only driven for 7,200 miles, it’s up to the manufacturers to interpret the data and figure out how long it would last in theory if driven until it were out of tread. This interpretation can be more conservative or optimistic depending on who is examining the data, and this is partially why treadwear comparisons are relative within each manufacturer and not across multiple brands.
While not a foolproof method, it is common in the tire world to add 2 zeros to the end of this number for approximate tread life. In the above example, the treadwear rating is 520, so a tire tech may estimate the tread life of that tire at around 52,000 miles. It’s very important to recognize that this is not a steadfast rule, and tread life is impacted by many outside factors that have nothing to do with this rating. It’s common to see a tire’s life be considerably shorter or longer than this estimated number, so don’t make the mistake of assuming it’s the only indicator of a tire’s longevity.
This is the second portion of the rating, and is a 1- or 2-letter rating. It indicates a tire’s ability to stop on a straight, wet surface (not on snow/ice, and not its cornering abilities). The ratings, from highest to lowest, are AA, A, B, and C. AA and A are pretty common on higher quality, new model passenger tires, and should both be considered adequate for use in the DC metro area. In the above example, we can see that the traction rating is an A. (The AA rating is often found on summer tires, high performance tires, or racing tires that all require a heavy focus on traction.)
This is the third portion of the rating, and is a 1-letter rating. It’s a measure of how heat is both generated and dissipated from the tire. From highest to lowest, they read A, B, and C. The higher the grade, the better resistance the tire has to deformation and degradation from heat at high speeds. These ratings are similar to the speed ratings of tires, as they do correlate to what speed they can be used at (since speed generates heat). Grade A can withstand over 115 mph, grade B can withstand between 100-115 mph, and grade C can withstand between 85-100 mph. In the above example, the temperature rating is A. In general, A and B are both adequate to use in the DC metro area (legally, all tires sold in the U.S. with UTQG ratings have to have a C or better).
While UTQG ratings are meant to help consumers better understand the quality of the tires they are considering, they sometimes fall a little short. Not only are they a little complicated, but since there is no standard across all brands for treadwear, it’s often difficult to determine what a tire’s longevity truly is. With that being said, it’s still a relatively good indicator of overall quality, and it’s definitely a useful piece of knowledge to have in mind the next time to go shopping for tires. At Wiygul Automotive Clinic, our tire experts really know their stuff, and would be happy to answer any questions you may have about your next tire purchase and their related UTQG ratings. Stop in to any of our convenient locations and we’ll get your vehicle fitted with the perfect set of tires in no time!