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uuChecking and Maintaining Tires uDOT Tire Quality Grading (U.S. Vehicles)
Maintenance
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 asph alt and concrete. A tire marked
C may have poor traction performance.
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 te sted 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 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 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.
■Traction
■Temperature
1 Traction
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.
1Temperature
Warning: The temperature grade for
this tire is establishe d 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.
