DOT Quality Grades
tires must meet under the Federal Motor Vehi-
cle Safety Standard No. 109. Grades B and A
represent higher levels of performance on the
laboratory test wheel than the minimum
required by law.
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.<
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 sep-
arately or in combination, can cause heat
buildup and possible tire failure.<
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
M+S
Winter and all-season tires.
These have better winter properties than sum-
mer tires.
150 would wear one and one-half (1
γ) 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 characteris-
tics and climate.
XL
Indicates specially reinforced tires.
Tire condition
Traction
Inspect your tires frequently for tread wear,
signs of damage and for foreign objects lodged
in the tread. Check the tread depth.
The traction grades, from highest to lowest, are
AA, A, B, and C.
These 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.
Minimum tread depth
The tread depth should not drop below 0.12 in/
3
mm, although, for example, European legisla-
tion only specifies a minimum tread depth of
0.063 in/1.6 mm. At tread depths below 0.12 in/
The traction grade assigned to this tire is
based on straight-ahead braking traction
tests, and does not include acceleration, cor-
nering, hydroplaning, or peak traction charac-
teristics.<
3
mm there is an increased risk of high-speed
hydroplaning, even when only small amounts of
water are present on the road surface.
When winter tires wear down past a tread depth
of 0.16 in/4 mm, they become perceptibly less
suitable for winter conditions. For the sake of
safety, new tires should be installed.
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 temperature can lead to
sudden tire failure. The grade C corresponds to
a level of performance which all passenger car
202
Online Edition for Part no. 01 41 0 014 238 - © 08/07 BMW AG
| Categories | BMW 5-Series Manuals, BMW Manuals |
|---|---|
| Tags | BMW E60, BMW M5 |
| Model Year | 2008 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
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