Wheel/tire condition, Tire identification marks wheel/tire condition – BMW X5 4.8is SAV 2004 User Manual

Page 145

143

Tire identification marks

Wheel/tire condition

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 speci-
fied 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 charac-
teristics.

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 condi-
tions 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 tem-
perature can lead to a sudden flat tire.
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.

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 a tire failure.

M+S

Winter and all-season tires.
These have better winter properties
than summer tires.

Wheel/tire damage

Inspect your wheels and tires frequently
for tread wear, signs of damage and for
foreign objects lodged in the tread.
Check the tread pattern depth.

Due to low-profile tires, please
note that wheels, tires and sus-

pension parts are more susceptible to
road hazard and consequential dam-
ages. Unusual vibrations encountered
during normal vehicle operation can
indicate tire failure or some other vehi-
cle defect. This can, for example, be
caused by driving over curbs. This is
also true for irregularities in the vehi-
cle's handling characteristics, such as a
pronounced tendency to pull to the left
or right. Should this occur, respond by
immediately reducing your speed.
Carefully proceed – or have your vehi-
cle towed – to the nearest BMW Sports
Activity Vehicle center or tire dealer to
have the wheels or tires inspected.
Tire damage, extending to sudden and
complete loss of pressure in extreme
cases, can pose a potentially lethal
safety hazard for the vehicle's occu-
pants and other road users alike.