Uniform Tire Quality Grading System
Few consumer products on the market today offer the reliability and value of modern automobile tires. Their dependability is very high, especially considering their complexity and the demanding driving and road conditions to which they are subjected during their lifetime.
But buying new tires can be confusing. Many people rely on recommendations from service stations or tire dealers where they have been treated well in the past, buy from a store that offers a variety of brands at discount prices, or make their decision based on the loyalty to a certain manufacturer whose tires have given good service previously. regardless of where you buy them...or how much you pay...all tires sold today are required to meet federal safety standards.
Many consumers wonder what they should look for when shopping for new tires. For example, "Is a $65 tire 'better' than a $45 one?" The answer to that question is, "Maybe but not necessarily." Some tire buyers are likely to assume that the higher the price... the 'better' the tire. Tire advertising can further complicate the decision on what tire to buy. A "premium" tire from one manufacturer can be quite different from another company's "premium" tire.
The truth is how the tire is used, your personal driving style, the type of vehicle you drive, where you drive and what kind of tire maintenance you perform routinely can influence tire life more than the brand name and the price paid.
The Uniform Tire Quality Grading System (UTQGS) is a tire information system designed to help buyers make relative comparisons among tires. The UTQGS is not a safety rating and not a guarantee tat a tire will last for a prescribed number of miles of perform in a certain way. It simply gives tire buyers additional information to combine with other considerations, such as price, brand loyalty and dealer recommendations. Under UTQGS, tires are graded by the manufacturers in three area: treadwear, traction and temperature resistance.
The UTQGS information is right where you need it...on the tires. The grades can be found on two places on the tire:
Additionally, brochures which explain the tire grades are available at tire stores.
The treadwear grade is a comparative rating based on the wear rate of the tire when tested under carefully controlled conditions. For example, a tire graded 200 should have its useful tread last twice as long as a tire graded 100. However, real world tire tread life, in miles, depends on the actual conditions of their use. Tire life is affected by variations in driving habits, service practices...such as tire rotation, wheel alignment and maintaining proper inflation pressure...and differences in road characteristics and climate.
Traction grades represent the tire's ability to stop on wet pavement as measured under controlled conditions on asphalt and concrete test surfaces. The traction grades from highest to lowest, are "AA", "A", "B" and "C". A tire graded "AA" may have relatively better traction performance than a tire graded "A", "B" or "C", based on straight ahead braking tests. The grades do not reflect the cornering or turning traction performance of the tires.
Temperature grades represent the tire's resistance to heat and its ability to dissipate heat when tested under controlled laboratory test conditions. Sustained high temperature can cause the tire to degenerate and reduce tire life, and excessive temperature can lead to sudden tire failure. The temperature grades from highest to lowest are "A", "B" and "C". The grade "C" corresponds to the minimum performance required by federal safety standard. Grades "B" and "A" represent higher levels of performance than the minimum required by law. The temperature grade is for a tire that is inflated properly and not overloaded. Excessive speed, underinflation or excessive loading, either separately on in combination, can cause heat build-up and possible tire failure.
The Uniform Tire Quality Grading Report
(244K) lists important information regarding most major brands of tires. You can also search for a subset of the information if you so desire.Additional information can be found in the Motorists's Tire Care and Safety Guide from the Tire Industry Safety Council.
| 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 loose 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. |
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