Manufacturers give each tire UTQG rating.  Learn what this rating means and what it tells you about the tire.

Treadwear

The treadwear grade is a comparative rating based on the wear rate of the tire when tested undercontrolled conditions on a specified government test course. For example, a tire graded 150 would under one and a half (1½) times as well on the government course as a tire graded 100. The relative performance of tires depends upon the actual conditions of their use, however, and may depart significantly from the norm due to variations in driving habits, service practices and differences in road characteristics and climate.

Traction - AA, A, B AND C:

The traction grades from highest to lowest are AA, A, B and C and they represent the tire's ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tire marked C may have poor traction performance. The traction grade assigned to this tire is based on braking (straight ahead) traction tests and does not include cornering (turning) traction.

TEMPERATURE - A, B and C:

The temperature grades are A (the highest), B and C, representing the tire's resistance to the generation of heat and its ability to dissipate heat when tested under controlled conditions on a specified indoor laboratory test wheel. Sustained high temperature can cause the material of the tire to degenerate and reduce tire life, and excessive temperature can lead to sudden tire failure. The grade C corresponds to a level of performance which all passenger car tires must meet under the Federal Motor Vehicle Safety Standard No.109. Grades A and B represent higher levels of performance on the laboratory test wheel than the minimum required by law.The temperature grade for this tire is established for a tire that is properly inflated and not overloaded. Excessive speed, under inflation, or excessive loading, either separately or in combination, can cause heat buildup and possible tire failure.

Q.
What does the TREADWEAR grade tell about a tire?
A.
The higher the number, the greater tread life you should expect. A tire with a grade of 200 should give you twice as much mileage as one rated at 100, provided that you keep the tires inflated properly, the wheels aligned and tires balanced and drive then under normal conditions.
Failure to care for your tires will greatly reduce the tread life and can also create a safety hazard. How you drive, and under what road conditions, also affects treadwear.
 
Q.
So the TREADWEAR grade will not tell me for certain how many miles of tread life I can expect?
A.
Correct. It is not a measure of tread life. It indicates on that, under the same general conditions, one tire can be expected to produce more mileage than another, not what the mileage will be. Again, actual tread life is strongly influenced by where you live and how you drive. In some parts of the country, tires wear out faster.
For example, the local rock used for road construction is rougher in some geographical area than in others. The same tire might give 20,000 miles in one part of the country and 30,000 in another, but a tire with a higher grade should produce better tread life than a lower graded tire in either locality.
 
Q.
Will all drivers get the same mileage on the same grade of tire?
A.
No. Mileage is determined primarily by driving habits. Drivers who start off slowly can expect the best tread life. Those who consistently make "jack rabbit" starts and stops and fast tire screeching turns will get the least.
Studies have shown that treadwear for the same tire can be as low as 14,000 for some drivers, but as high as 30,000 miles for other drivers in the same geographical area.
Proper maintenance is also important. Under- or over-inflation, unbalanced wheels and wheel misalignment results in uneven treadwear that causes the tire to wear out prematurely.
 
Q.
What does the TRACTION grade tell me about the tire?
A.
In a straight line stop, the "AA" graded tire should allow you the stop your car on wet roads in a shorter distance than tires graded "A", "B" or "C". When driving on wet roads, good traction is important to your safety. Tires graded "C" offer the least traction on wet roads.
 
Q.
Is the ability to stop the car affected by anything besides the tire grade?
A.
Yes. When the tread is badly worn, all tires lose much of their stopping ability, especially on wet roads.
For safety reasons, it is important to replace tires when the built-in treadwear indicators begin to show (you will see lines across the tread when the groves measure only 1/16 of an inch deep (about the thickness of a nickel).
Regardless of the traction grade a bald tire is dangerous. Keep in mind, that properly maintained brakes are also extremely important to stopping performance.
 
Q.
Is TRACTION improved if you let some of the air out of the tires, below the recommended pressures?
A.
No. In fact, this is a dangerous practice. Underinflation does not improve traction. It causes the tire to run hot, which can damage it and increase the risk of a blowout. It will also wear out the tread faster and reduce your car's fuel economy.
Proper tire pressure information can be found in the vehicle owner's manual and on the tire information placard on the vehicle.
 
Q.
What does the TEMPERATURE RESISTANCE grade tell me about a tire?
A.
Sustained high temperatures can cause the tire material to degenerate and excessive temperatures can lead to blowouts and tread separations. The "A" rating signifies the coolest running tire.
If the vehicle and tires are maintained and operated properly, they should perform safely and reliably when run at the speed limit, even in very hot weather. "C" tires run hotter than tires graded "A" or "B", but a "C" graded tire is not "UNSAFE".
Keep in mind that under-inflation or overloading will overheat and damage any tire and greatly increase the likelihood of a blowout.
 
Q.
What significance does the TEMPERATURE RESISTANCE grade have for me as a driver?
A.
If you often drive at highway speeds for periods of an hour or more, there is less chance a cooler-running "A" graded tire will overheat than a "B" or "C" graded tire.
All tires should perform safely and reliably when driven at the speed limit, but higher graded tires will give you a greater margin of safety. Your individual driving habits and the amount of time you spend driving in hot climates or at highway speeds should determine how much emphasis you put on the temperature resistance grade.
 
Q.
Is the temperature of my tires affected by anything other than the assigned grade?
A.
Yes. All tires will run a higher temperatures when they are underinflated or over loaded.
It is very important to check the pressure in all of your tires before starting out on a trip where you will be driving at highway speeds for more than an hour. Always inflate the tires to the recommended pressures before starting on the trip. This precaution will help any tire run cooler.