UTQG, or Uniform Tire Quality Grade, is a Federal government mandated test system for tires. All commercial tires to be sold in the USA require the UTQG rating in order to be legally sold. In order to obtain the rating, there is a strictly outlined test which the tire manufacturer must place on their tire model. UTQG outlines 3 areas of a tires’ performance and quality:
- temperature resistance
Treadware is based of a standard of 100. A number lower than 100 has a treadware lower than the norm, while conversely a treadware higher than 100 is above the norm. Each tire is put through a 7200 mile test. It is then graded on how far it is away from 2/32″ of tread left on the tire to give it a final grade. In simple terms, the closer to 2/32″, the lower the number. The real answer is a bunch of math that they use to take the 7200 mile wear factor, and extrapolate it down to 2/32″ to get the expected life of a tire.
Based off the 100-norm, a tire that receives a 200 treadware rating is said to be able to last twice as long as the defined norm, and a 50 treadware tire is said to last half as long as the norm. A key point is that these are percents, and not solid integer ranges. The difference from 50 to 100 VS 100 to 150 is the same 50 integer, but it is not the same differential. 50 treadware is 50% the norm, where was 150 is 150% of the norm, not double. In order to match, 150 would really need to be 200. (1/2 VS 2/1 inverse fractions). Therefore, keep in mind that the difference in treadwares between a low group, say a 40 and a 50, and a high group, say 400 and 410 are DRASTICALLY different. The 400 and 410 are very close, where as the 40 and 50 are literally “miles” away from each other in terms of longevity.
The average street sport tire falls in the 140-300 range. “Touring” tires are usually 400 and even as high as 600. DOT-approved R-comps are usually in the double digits, 30-70
The traction test is not done on dry pavement much to many people’s disbelief. The test is performed on both asphalt and cement in the wet from 40mph. It needs to be noted that the traction test does not factor in acceleration tests, cornering tests, or any dry tests. Furthermore, it has nothing to do with hydroplane resistance. The test is merely the stopping traction on a wet surface from 40mph.
The test is a pass/fail, with a grade given as follows:
- Grade A: The tire performed well on both the asphalt and cement surfaces
- Grade B: The tire performed well on at least one of the surfaces
- Grade C: The tire performed poorly on one or both of the surfaces
In 1997, a new grade, AA came out. This grade is above Grade A and is usually found on today’s ultra high performance tires. With it, came a coefficient of traction guideline:
|Traction Grades||Asphalt g force||Concrete g force|
|C||Less Than 0.38||0.26|
The final part is the temperature resistance test. This test is performed in a controlled environment and uses a wheel with force pushing against a surface, similar to a dyno. Speed, load and inflation pressure can significantly impact a tire’s resistance to heat generation or build-up, which in turn can reduce a tire’s durability and service life. Thus, the test is conducted under predetermined standards for inflation and loading.
Like the Treadware rating, it is a letter grade of one of the following results:
- Grade A: Maximum performance level indicating the tire withstood a 30-minute run at 115 mph without failing
- Grade B: The tire passed 100 mph, but not 115 mph
- Grade C: Minimum performance level indicating the tire failed to complete a half-hour at 100 mph
Putting the Pieces Together
The 3 sections make up the UTQG rating of the tire. It is shown on the sidewall of the tire in one of two formats:
- Long Hand
Abbreviated ratings will look something like this on the sidewall:
200 AA A
Long hand ratings will look something like this on the sidewall:
Treadware: 200 Traction: AA Temp: A