Uniform Tire Quality Grading
ALL PASSENGER VEHICLE TIRES MUST CONFORM TO FEDERAL SAFETY REQUIREMENTS IN ADDITION TO THESE GRADES
Quality grades can be found, where applicable, on the tire sidewall between the tread shoulder and maximum section width. For example:
Treadwear 200 Traction AA Temperature A
TREADWEAR
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 many depart significantly
from the norm due to variation in driving
habits, maintenance practices and differences
in road characteristics and climate.
TRACTION
The traction grades, from highest to lowest, are
AA, A, B, and C, 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 braking (straight-ahead) traction
tests and is not a measure of cornering
(turning) traction.
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 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 minimum level of performance that all passenger vehicle 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
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
buildup and tire failure.
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