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DOT Tire Quality Grading
The tires on your vehicle meet all U.S. Federal Safety Requirements. All tires are
also graded for treadwear, traction, and temperature performance according to
Department of Transportation (DOT) standards. The following explains these
gradings.
Uniform Tire Quality Grading
Quality grades can be found where applicable on the tire sidewall between tread
shoulder and maximum section width.
For example:
Treadwear 200
Traction AA
Temperature A
All passenger car tires must conform to Federal Safety Requirements in addition
to these grades.
Treadwear
The treadwear grade is a comparative rating based on the wear rate of the tire
when tested under controlled conditions on a specifi ed 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
signifi cantly 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 specifi ed 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 acceleration, cornering, hydroplaning,
or peak traction characteristics.
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 specifi ed 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 temperature grade for this tire is established for a tire that
is properly infl ated and not overloaded. Excessive speed, underinfl ation, or
excessive loading, either separately or in combination, can cause heat buildup
and possible tire failure.
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