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SERVICING AND MAINTENANCE
DEPARTMENT OF TRANSPORTATION
UNIFORM TIRE QUALITY GRADES
The following tire grading categories
were established by the National High-
way Traffic Safety Administration. The
specific grade rating assigned by the
tire's manufacturer in each category is
shown on the sidewall of the tires on
your vehicle.
All passenger vehicle tires must con-
form 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 specified government test course.
For example, a tire graded 150 would
wear one and one-half 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 sig-
nificantly from the norm due to varia-
tions in driving habits, service practices,
and differences in road characteristics
and climate.
TRACTION GRADES
The Traction grades, from highest to
lowest, are AA, A, B, and C. These
grades represent the tire's ability to
stop on wet pavement, as measured
under controlled conditions on speci-
fied 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 GRADES
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 condi-
tions 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 tem-
perature can lead to sudden tire fail-
ure. The grade C corresponds to a level
of performance, which all passenger
vehicle tires must meet under the Fed-
eral Motor Vehicle Safety Standard No.
109. Grades B and A represent higher
levels of performance on the labora-
tory 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.
(Continued)
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