UNIFORM TIRE QUALITY GRADING
DOT (Department Of Transportation)
Quality Grades: All passenger car tires
must conform to federal safety require-
ments in addition to these grades.
Quality grades can be found where ap-
plicable on the tire sidewall between
tread shoulder and maximum section
width. For example:
all passenger car tires must meet under
the Federal Motor Vehicle Safety Stan-
dard No. 109. Grades B and A represent
higher levels of performance on the
laboratory test wheel than the minimum
required by law.
TRACTION AA, A, B AND C
The traction grades, from highest to low-
est, 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 concrete. A tire
marked C may have poor traction perfor-
mance.
WARNING
Treadwear 200 Traction AA Tempera-
ture A
The temperature grade for this tire is
established for a tire that is properly
inflated and not overloaded. Exces-
sive speed, under-inflation, or exces-
sive loading, either separately or in
combination, can cause heat build-
up and possible tire failure.
TREADWEAR
WARNING
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
The traction grade assigned to this
tire is based on straight-ahead brak-
ing traction tests, and does not
include acceleration, cornering, hy-
droplaning, or peak traction charac-
teristics.
(1 1/2) times as well on the government
course as a tire graded 100. The relative
performance of tires depends upon ac-
tual conditions of their use, however, and
may depart significantly from the norm
due to variations in driving habits, service
practices and differences in road charac-
teristics and climate.
TEMPERATURE A, B AND C
The temperature grades 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 con-
trolled 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 corre-
sponds to a level of performance which
10-16 Technical and consumer information
