What does 400AA in tires mean?
Understanding Tire UTQG Ratings: What They Mean and Why They Matter
When shopping for new tires, you’ve probably seen a series of numbers and letters printed on the sidewall — something like “TREADWEAR 400, TRACTION A, TEMPERATURE B.” These are called UTQG ratings, short for Uniform Tire Quality Grading, and they provide valuable insight into how a tire performs in three critical areas: treadwear, traction, and temperature resistance. Understanding these ratings can help you make a smarter decision when choosing tires that fit your driving habits and needs.
What Is the UTQG System?
The UTQG system was established by the U.S. Department of Transportation (DOT) to help consumers compare tire performance. All passenger car tires sold in the United States (except for winter tires, light truck tires, and some specialty tires) must have a UTQG rating. The grading is conducted by manufacturers according to government guidelines, though it’s important to note that these tests are not independently verified — they are self-reported by the tire makers.
Treadwear Rating
The treadwear rating indicates how long the tire’s tread is expected to last compared to a control tire rated at 100. For example, a tire with a treadwear rating of 400 should, theoretically, last four times longer than the control tire under identical conditions. However, this is only a comparative figure — real-world results depend on driving style, maintenance, road conditions, and climate. A tire rated 600 will generally last longer than one rated 300, but longevity can vary greatly between brands.
Traction Rating
The traction rating measures how well a tire can stop on wet pavement. It’s graded from AA, A, B, to C, with AA being the highest. A tire with an “A” traction rating provides strong wet grip and braking performance, which is crucial for safety in rainy conditions. It’s worth noting that this rating focuses solely on straight-line braking — it doesn’t account for cornering or hydroplaning resistance.
Temperature Rating
The temperature rating represents a tire’s ability to withstand and dissipate heat at high speeds. Tires are graded A, B, or C, with “A” offering the best heat resistance. Excessive heat can cause a tire to degrade or even fail, especially during highway driving in hot climates. Therefore, a higher temperature rating generally indicates a more durable tire suitable for sustained high-speed travel.
Why UTQG Ratings Matter
Although UTQG ratings are not perfect — since they rely on manufacturer testing rather than independent verification — they still serve as a useful benchmark. For instance, if you drive long distances on highways, a tire with a high treadwear number and an “A” temperature rating might be ideal. Conversely, if you prioritize grip and handling for performance driving, you might prefer a tire with a lower treadwear rating but higher traction.
Final Thoughts
UTQG ratings are a helpful tool for comparing tires, but they shouldn’t be your only consideration. Factors like ride comfort, road noise, and seasonal performance are also important. By understanding what these numbers and letters mean, you can make a more informed decision — ensuring your tires deliver the right balance of durability, safety, and performance for your driving style.
