Mercedes-Benz GLC : Tire labeling / Tire Quality Grading

In accordance with the US Department of Transportation's "Uniform Tire Quality Grading Standards", tire manufacturers are required to grade their tires on the basis of the following three performance factors:

Tread wear grade

Traction grade

Temperature grade

The data shown in the illustration is example data.

The classification is not legally stipulated for Canada, but it is generally stated.

Tread wear grade

The treadwear 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 conditions.

Traction grade

DANGER Risk of accident due to inadequate traction

The traction grade assigned to this tire is based on straight-ahead braking traction tests.

Always adapt your driving style and drive at a speed to suit the prevailing traffic and weather conditions.

NOTE Damage to the drivetrain from wheelspin

Avoid wheelspin.

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 grade

WARNING Risk of accident from tire overheating and tire failure

Excessive speed, underinflation, or excessive loading, either separately or in combination, can cause excessive heat build-up and possible tire failure.

Observe the recommended tire pressure.

Regularly check the pressure of all the tires.

Adjust the tire pressure, if necessary.

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 Safety Standard No. 109. Grades B and A represent higher levels of performance on the laboratory test wheel than the minimum required by law.