You may not hear about UTQG but most of you probably see the words ‘Treadwear’, ‘Traction’, and ‘Temperature’ on the sidewall of your tires.
UTQG stands for Uniform Tire Quality Grade and it contains useful information for customers. Let’s dive into its process and what each grade indicates and how can you use them for your tire selection!
Note: Light truck and winter tires aren’t require a UTQG test.
How do UTQG Grades Determine?
Even though some think these tests are conducted by DOT or NHTSA, in fact, manufacturers or 3rd parties conduct this test and report to DOT. However, due to privacy policies, DOT can’t publish detailed test results but only the grades. DOT rearranges these data and publishes a brief and simple version of the test results.
UTQG Test Process
The test process is different for each grade.
- Treadwear Grade: Actual road use in West Texas. The test circuit is 400-miles long and the tire takes 18 laps(a total of 7200-miles).
- Traction Grade: The test tires are pulled on a “skid trailer” at 40mph over wet asphalt and concrete test surfaces
- Temperature Rating: This is an indoor test. Generally conducted by 3rd parties. The tire run against a high-speed drum.
This test is performed under the actual conditions. Therefore, it might seem a bit more accurate than the others for you. Unfortunately, it’s wrong.
The tire runs only 7200-miles which is a nominal mileage compared to the real life span of the tires(50,000-100,000 miles). Moreover, the compound of the tire has different layers. For instance, while the first couple millimeters of tread are made of firm rubber, the rest can be made of softer rubber. Obviously, soft rubber wears faster. So, the extrapolation of the manufacturers becomes kinda useless in that case.
Restrictions of the test,
- Each lap takes 400-miles
- Tires are rotated in every 800-miles
- Wheels are aligned in every 800-miles
- Inflation pressure is checked in every 800-miles
Under the above rules, the test tire and reference tire run in the same conditions. After the 7200-miles have been done, the tread depth of both tires is checked.
The reference tire always has a treadwear great of 100. So, if the test tire and reference tire have the same tread depth, the UTQG of the test tire is also 100.
For instance, if the test tire is expected 2 times more than the reference tire, then the UTQG of the test tire is 200. So, for a simple comparison, you may divide UTQG numbers by 100.
In my point of view, the most efficient usage of UTQG treadwear is comparing two tires. For example, you’re debating between two tires. While one of them has a 250 UTQG grade other has 600. In that case, the tire with 600 grade is expected to last 2.4 times longer(if 250 grade lasts for 10,000 miles, 600 grade lasts for 24,000 miles).
If you’d like to learn how to get the longest tread life –> https://tireterrain.com/how-to-make-tires-last-longer/
The traction grade is based on the stopping distance on the wet ground. Though worth reminding, this grade doesn’t indicate dry performance or any other wet performance like hydroplaning or cornering.
The test tires pull a ‘skid trailer’ at 40 mph. The brakes are locked for a short time in a period. So, the sensor on the wheel measures the coefficient of a locked tire. Well, after a couple of calculations, the coefficient turns into a wet stopping distance.
Since the majority of vehicles have anti-locked brakes, this test isn’t aligned with real-life conditions. However, it can still give you an idea about wet stopping distance.
The test is conducted on two different surfaces Asphalt and concrete. Depending on the surface, the grade limits change.
|Traction Grades||Asphalt g-Force||Concrete g-Force|
|C||Less Than 0.38||0.26|
The heat is the enemy of the tire. So, the temperature grade simply measures the heat resistance of the tire.
The better heat resistance means that the tire can reach a higher speed.
Since all tires have a speed index, the main goal of this test is how the tires act on a long run at high speed.
|Temperature Grades||Speeds in mph|
|B||Between 100 to 115|
|C||Between 85 to 100|
While A means higher temperature resistance, C states the lowest one. Though worth reminding, the tires don’t reach at least C level can’t be released in the USA.
UTQG ratings are the assurance of the government. So, using them for comparison isn’t accurate. The grades can give you and preliminary idea. Yet, you should know that these are calculations, not real-life data.
I hope the article was helpful. If you have any further questions, please leave them in the below section. Have a safe ride folks!
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