Operation Manual

Uniform Tire Quality Grading
Standards
The Uniform Tire Quality Grading is a U.S.
Government requirement designed to give
drivers consistent and reliable
information regarding tire performance.
Tire manufacturers are required to grade
tires based on three performance factors:
treadwear :, traction ;, and temperature
resistance =. Although not a Government
of Canada requirement, all tires made for
sale in North America have these grades
branded on the sidewall.
i
For illustration purposes only. Actual
data on tires are specific to each vehicle
and may vary from data shown in above
illustration.
Quality grades can be found, where
applicable, on the tire sidewall between
tread shoulder and maximum section width.
For example:
Treadwear Traction Temperature
200 AA A
All passenger car tires must conform 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 U.S. 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 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
G
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. 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
performance.
Temperature
G
Warning!
The temperature grade for this tire is
established for a tire that is properly
inflated and not overloaded. Excessive
speed, underinflation, or excessive
loading, either separately or in
combination, can cause excessive heat
build-up 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
Tires and wheels
137
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BA 451 USA, CA Edition A 2011; 1; 4, en-US
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