UNIFORM TIRE QUALITY GRADING
DOT (Department of Transportation) Qual- ity Grades: All passenger car tires must conform to federal safety requirements in addition to these grades. Quality grades can be found where appli- cable on the tire sidewall between tread shoulder and maximum section width. For example:
Treadwear 200 Traction AA Temperature A Treadwear The treadwear grade is a comparative rat- ing based on the wear rate of the tire when tested under controlled conditions on a specified government test course. For ex- ample, 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 AA, A, B and C The traction grades, from highest to low- est, are AA, A, B, and C. Those grades repre- sent the tire's ability to stop on wet pave- ment as measured under controlled
conditions on specified government test surfaces of asphalt and concrete. A tire marked C may have poor traction performance.
WARNING The traction grade assigned to this tire is based on straight-ahead braking traction tests, and does not include ac- celeration, cornering, hydroplaning, or peak traction characteristics.
Temperature A, B and C The temperature grades are A (the high- est), B, and C, representing the tire’s resis- tance 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 tem- perature can cause the material of the tire to degenerate and reduce tire life, and ex- cessive 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 Mo- tor Safety Standard No. 109. Grades B and A represent higher levels of performance on the laboratory test wheel than the mini- mum required by law.
WARNING 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 combi- nation, can cause heat build-up and possible tire failure.
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