Your tire has a wide assortment of numbers and letters on it and some are more important than others. In the past, we’ve covered the information presented on your tire size code and speed ratings, and now we’ll cover the Uniform Tire Quality Grading (UTQG). You won’t specifically see the letters “UTQG” anywhere on your tire, rather UTQG represents your vehicle’s treadwear, traction, and temperature grades (or ratings). This is indicated by number and letter grades, with the former for treadwear and the latter for traction and temperature. You should see the actual words “treadwear”, “traction”, and “temperature” on most tires and those three values represent the tire’s UTQG rating.
In this guide, we’ll cover the basics of UTQG before going into detail on how those values are determined and how much value you should place in them when shopping for your tires.
The treadwear rating on your tire is designated by a three-digit number and is actually a comparative rating. That means the rating is done in comparison to a reference tire, and is not a clear indicator of how long a tire will last. For example, a tire with a rating of 300 will last three times as long as a tire rated at 100. Unfortunately that doesn’t equate to a value of how many miles your tire will last. More importantly, the tire manufacturer or a third-party testing company conducts the tests that determine the tire’s treadwear rating.
That test involves the tire being ran in a convoy on a 400-mile test loop in Texas for a total of 7,200 miles. During the test, the vehicle is allowed to set its alignment, check its air pressure, and the tires can be rotated every 800 miles. After 7,200 miles, a measurement is made to check the wear on the tires and that is compared to a reference tire (determined by the manufacturer) that underwent the same test. If the tested tire is expected to last as long as the reference tire, it will get a treadwear rating of 100. If the tested tire is expected to last twice as long, its treadwear rating would be 200.
But this isn’t a reliable rating, since the tires are only tested for 7,200 miles and under certain conditions. That means the manufacturer or third-party company extrapolates the rest of the data and that may not be entirely accurate. In addition, the manufacturer is allowed to underrate the treadwear rating, but not overrate it. So if a tire is able to achieve a 500 treadwear rating, the manufacturer may choose to rate it at 300 if it makes it a better fit in the segment.
Tire Rack recommends only comparing treadwear ratings on tires from the same manufacturer and to avoid comparing ratings across different brands.
The traction rating is more straightforward than the treadwear rating since it’s represented by one of the following grades (from highest to lowest): AA, A, B, and C. The grade is an indicator of how well the tire performs in wet conditions, specifically its ability to stop on wet pavement. This is measured in a controlled test based on government specifications, again by the tire manufacturer or a third-party testing company.
For the test, the tire is pulled on what is called a skid trailer at 40 mph on wet asphalt and concrete surfaces. The brakes are then locked and sensors measure the coefficient of friction while the tire skids. There is a catch however, as Tire Rack points out: “Since the vast majority of vehicles on the road today have anti-lock brakes, tire manufacturers design their products to work more effectively with these systems, as opposed to at full lockup.” That means traction ratings aren’t as applicable in modern vehicles, since the test was originally designed for vehicles with much older technology.
Below, you’ll find a table for each traction rating and its respective asphalt and concrete g-Force ratings.
|Traction Grade||Asphalt g-Force||Concrete g-Force|
|AA||Greater than 0.54||0.38|
|A||Greater than 0.47||0.35|
|B||Greater than 0.38||0.26|
|C||Less than 0.38||0.26|
One thing to keep in mind with traction rating is that the test doesn’t account for dry performance, cornering, or hydroplaning resistance. It’s simply a test that measures the coefficient of friction on a locked tire in a straight line on two different wet surfaces.
The temperature rating is similar to the traction rating, where it’s awarded a grade following a test. The temperature grades (from highest to lowest) are A, B, and C. This grade indicates how well a tire can resist heat and is measured with an inflated tire running against a high-speed test drum. The table below explains each rating and the speeds at which the tire is able to perform.
|Temperature Grade||Speeds (mph)|
|A||Greater than 115 mph|
|B||Between 100 mph to 115 mph|
|C||Between 85 mph to 100 mph|
What you need to know about the UTQG standards
The National Highway Traffic Safety Administration (NHTSA), along with the U.S. Department of Transportation (DOT) created the UTQG standards in 1978. Although they are helpful by providing a set of standards, UTQG isn’t used by the entire industry. Also, some tires including spare tires, trailer tires, winter tires, light truck tires, non-passenger car tires, and tires smaller than 12″ in diameter are not required to have UTQG ratings.
The testing can also be seen as flawed, since the manufacturers are conducting it or hiring a third-party company. That means there isn’t just one company doing all the testing, but several. The results can also be a bit inaccurate since there are limitations to the tests. For example, each manufacturer chooses their own baseline tire to grade against, which means test results aren’t the same across different tire manufacturers. As we mentioned earlier, it’s best to compare UTQG ratings for tires within the same brands.
Most importantly, it’s best to not shop for tires based solely on UTQG ratings. It’s a good starting point, but isn’t enough to make an informed purchasing decision.