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Uniform Tire Quality Grading
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
DOT Quality Grades
Treadwear
Traction AA A B C
Temperature A B C
Conform to Federal Safety Requirements
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 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 the actual conditions of
their use, however, and may depart signifi‐
cantly from the norm due to variations in driv‐
ing habits, service practices and differences in
road characteristics and climate.
Traction
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.
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
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 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 represent higher levels of performance
on the laboratory test wheel than the minimum
required by law.
Temperature grade for this tire
The temperature grade for this tire is es‐
tablished for a tire that is properly inflated and
not overloaded. Excessive speed, underinfla‐
tion, or excessive loading, either separately or
in combination, can cause heat buildup and
possible tire failure.◀
RSC – Run-flat tires
The symbol identifying run-flat tires is a circle
with the letters RSC on the sidewall, refer to
page 241.
M+S
Winter and all-season tires.
These have better winter properties than
summer tires.
XL
Designation for specially reinforced tires.
Tire tread
Summer tires
Do not drive with a tire tread depth of less than
0.12 in/3 mm.
Seite 238
Mobility Wheels and tires
238
Online Edition for Part no. 01 40 2 954 052 - II/15
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