Tire Information
UNIFORM TIRE QUALITY
GRADING
United States Department of
Transportation/Uniform Tire Quality
Grade
The following information relates to the tire
grading system developed by the National
Highway Traffic Safety Administration
(NHTSA) which will grade tires by tread
wear, traction and temperature
performance.
Note: Tires that have deep tread, and winter
tires, are exempt from these marking
requirements.
Quality grades, where applicable, can be
found on the tire sidewall between the tread
shoulder and maximum section width.
For example:
In addition to the marking requirements,
passenger car tires must conform to
Federal Safety Requirements.
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 a half (1.5) times as well on a
government test course as a tire graded
100. The relative performance of tires
depends on the 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
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.
The traction grades, from highest to lowest,
are; AA, A, B, and C. These grades
represent a tire’s ability to stop on a wet
pavement as measured under controlled
conditions on specified government test
surfaces of asphalt and concrete. A tire
marked C may have poor traction
performance.
Temperature
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
combination, can cause heat buildup and
possible tire failure.
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 level of
performance which all passenger car tires
must meet under the Federal Motor Safety
Standard (FMVSS) No. 109.
Grades B and A represent higher levels of
performance on the laboratory test wheel
than the minimum required by law.
Treadwear
200
Traction
AA
Temperature
A
Owner's Handbook - US English.book Page 16 Friday, June 22, 2012 11:28 AM
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