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 gov-
ernment 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 characteristics
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 mea-
sured under controlled conditions on specified
government test surfaces of asphalt and con-
crete. 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, cor-
nering, 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.
Sustained high temperature can cause the ma-
terial 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 rep-
resent higher levels of performance on the
laboratory test wheel than the minimum re-
quired by law.
WARNING
The temperature grade for this tire is estab-
lished for a tire that is properly inflated and not
overloaded. Excessive speed, under-inflation,
or excessive loading, either separately or in
combination, can cause heat build-up and pos-
sible tire failure.
UNIFORM TIRE QUALITY GRADING
Technical information10-17
