Uniform Tire Quality Grading
UTQG is intended to provide simple, comparative data for your use in making an informed buying decision.
However, the ratings are based upon test results achieved under very specific conditions.
As a result, misinterpreting the comparative data as it relates specifically to your particular driving habits, conditions, etc.,
is a possibility. UTQG designates the comparative performance levels of a tire based upon government-specified tests.
Tire manufacturers and brand name owners are required to grade regular and all-season tires in three categories:
Treadwear, Traction, and Temperature.
DOT QUALITY GRADES
All passenger car tires must conform to Federal Safety Requirements in addition to these grades.
The treadwear grade is a comparative grade assigned by the manufacturer based on the wear rate of a tire when tested under controlled conditions on a
course that meets government-specified requirements.
For example, a tire graded 150 would wear one and a half (1 1/2) times as well as a tire graded 100 under the controlled test conditions.
The relative performance of tires depends upon the actual conditions of their use and may depart significantly from the norm due to variations in driving habits,
service practices and differences in road characteristics.
TRACTION AA, A, B, C
The traction grade is based on wet skid tests of a tire on government-specified concrete and asphalt surfaces.
The traction grade is based on a straight-ahead wet braking traction test and does not include a cornering traction test.
The comparative tire grade letters, AA, A, B, and C (AA being the highest and C being the lowest) represent the tire's
ability to stop the vehicle on wet pavement under the controlled test conditions.
Ice and snow traction capabilities are not tested.
The traction grade assigned is based on braking (straight ahead) traction test and does not include cornering (turning) traction.
TEMPERATURE A, B, C
The temperature grade is based on an indoor, high-speed test that meets government-specified requirements.
The comparative grade letters, A, B, and C (A being the highest and C being the lowest) represent 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 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.
A tire with the ratings of TREADWEAR 80, TRACTION B, TEMPERATURE C, is interpreted by the manufacturer as having:
- TREADWEAR grade less than that of a tire graded 100.
- TRACTION capability greater than tires of C grade, but not as good as tires of AA or A grade.
- TEMPERATURE performance on the laboratory high-speed test greater than required by the government standards, but less than tires graded B or A.
A tire with same brand name and same construction type with ratings of TREADWEAR 160, TRACTION A, TEMPERATURE B, compares to the tire in example #1 as follows:
- TREADWEAR is graded two times better than the tire in example #1.
- Wet TRACTION and TEMPERATURE are better than the tire in example #1.
Keep in mind that comparing the performance of various tires is too complex to be based exclusively on UTQG grades.
- UTQG grades are not government grades. They are manufacturer grades that are not based on head-to-head interbrand testing.
Test data is not typically submitted to the National Highway Traffic Safety Administration.
- Treadwear grades are not a guarantee for a given mileage warranty, or an indicator of overall tire quality.
Treadwear grades are assigned by the manufacturer for comparison purposes within the same brand names and construction types only.
- UTQG grades are not safety ratings. Overall tire quality and safety are not graded.
Tire selection based on any one, two, or even three UTQG ratings may not satisfy your needs.
- One brand name of tires cannot be considered superior or inferior to another brand name of tires based solely on UTQG grades.
- UTQG grades are not required for snow tires, light truck tires and maximum traction tires.
- UTQG is used but not required in Canada.