Uniform Tire Quality Grading; Tread Wear; Tire Condition - Mini Cooper Owner's Manual

Uniform Tire Quality Grading

Quality grades can be found where applicable
on the tire sidewall between tread shoulder and
maximum section width. For example:
Tread wear 200 Traction AA
Temperature A
DOT Quality Grades

Tread wear

Traction AA A B C
Temperature A B C
All passenger car tires must conform to
Federal Safety Requirements in addition
to these grades.<
Tread wear
The tread wear 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 (1γ) 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, how-
ever, and may depart significantly from the
norm due to variations in driving 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 con-
trolled 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 trac-
tion tests, and does not include acceleration,
cornering, hydroplaning, or peak traction
characteristics.<
Online Edition for Part no. 01 40 2 904 077 - © 03/12 BMW AG
Wheels and tires
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. Sus-
tained 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 Vehicle Safety
Standard No. 109. Grades B and A represent lev-
els of performance on the laboratory test wheel
that exceed the minimum required by law.
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 heat
buildup and possible tire
RSC - run-flat tires
You will recognize run-flat tires by a circular
symbol containing the letters RSC on the side of
the tire, page 218.
M+S
Winter and all-season tires.
These have better winter properties than
summer tires.
XL
Designation for specially reinforced tires.

Tire condition

Inspect your tires regularly for tread wear, signs
of damage and for foreign objects lodged in the
tread. Check the tread depth.
MOBILITY
failure.<
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