DOT (Department Of Transportation) Quality
Grades: All passenger car tires must conform to
federal safety requirements in addition to these
grades.
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
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 actual conditions of their
use, however, and may depart significantly from
the norm due to variations in driving habits,
service practices and differences in road char-
acteristics and climate.
TRACTION AA, A, B AND C
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 spe-
cified 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 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 controlled conditions on
a specified indoor laboratory test wheel. Sus-
tained 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
inflated and not overloaded. Excessive
speed, under-inflation, or excessive
loading, either separately or in combi-
nation, can cause heat build-up and
possible tire failure.
Technical and consumer information9-21
UNIFORM TIRE QUALITY GRADING
