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M
AINTENANCEMAINTENANCE
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 (D
oT) standards. The following explains these
gradings.
Uniform Tire Quality Grading
Quality grades can be found where applicable on the tire sidewall betwee\
n 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 th\
e 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) tim\
es 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, servi\
ce practices,
and differences in road characteristics and climate.
TractionThe 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 concre\
te. 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, hy\
droplaning,
or peak traction characteristics.
TemperatureThe 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 w\
hen tested
under controlled conditions on a specified indoor laboratory test whee\
l. Sustained
high temperature can cause the material of the tire to degenerate and re\
duce
tire life, and excessive temperature can lead to sudden tire failure. Th\
e 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 th\
an the
minimum required by law.
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 b\
uildup
and possible tire failure.
