Audi A6 Typ 4G: Uniform tire quality grading
- Tread wear
- Traction AA A B C
- Temperature A B C
Quality grades can be found where applicable on
the tire side wall between tread shoulder and
maximum section width
fig. 188.
For example: Tread wear 200, Traction AA, Temperature A.
All passenger car tires must conform to Federal Safety Requirements in addition to these grades.
Tread wear
The tread wear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test course.
For example, a tire graded 150 would wear one and one half (1 1/2) 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
The traction grades, from highest to lowest, are
AA, A, B and C. Those grades 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
.
Temperature
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 B and A represent higher levels of performance on the laboratory test wheel than the minimum required by law.
WARNING
The traction grade assigned to this tire is based on straight-ahead braking traction tests, and does not include acceleration, cornering, hydroplaning or peak traction characteristics.
WARNING
The temperature grade for this tire is established for a tire that is properly inflated and not overloaded. Excessive speed, underinflation, or excessive loading, either separately or in combination, can cause heat buildup and possible tire failure.
WARNING
Temperature grades apply to tires that are properly inflated and not over or underinflated.
