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Uniform Tire Quality Grading
Quality grades can be found where applica-
ble on the tire sidewall between tread
shoulder and maximum section width.
E.g.: Treadwear 200; Traction AA; Tempera-
ture A
DOT Quality Grades
Treadwear
Traction AA A B C
Temperature A B C
All passenger vehicle 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 government test course. E.g., a
tire graded 150 would wear one and one-
half, 1 g, times as well on the government
course as a tire graded 100. The relative
performance of tires depends upon the ac-
tual conditions of their use, however, and
may depart significantly from the norm due
to variations in driving habits, service prac-
tices 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 govern-
ment test surfaces of asphalt and concrete.
A tire marked C may have poor traction per-
formance.
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 material of the tire to degenerate
and reduce tire life, and excessive tempera-
ture can lead to sudden tire failure. The
grade C corresponds to a level of perform-
ance which all passenger car tires must
meet under the Federal Motor Vehicle
Safety Standard No. 109. Grades Band 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 es-
tablished for a tire that is properly inflated
and not overloaded. Excessive speed, un-
derinflation, or excessive loading, either
separately or in combination, can cause
heat buildup and possible tire failure.
RSC – Run-flat tires
Run-flat tires, refer to page 269, are labeled
with a circular symbol containing the let-
ters RSC marked on the sidewall.
M+S
Winter and all-season tires with better cold
weather performance than summer tires.
Seite 266
MOBILITY Wheels and tires
266
Online Edition for Part no. 01405A02CC9 - II/20
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