BMW X3 3.0si SAV 2007 - Manual (Page 96)

Wh
eels
and
tire
s
94
Temperature
The temperature grades are A, B, and C, A
being highest, and represent the tire’s resis-
tance 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 corre-
sponds to a level of performance that all pas-
senger 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 sep-
arately or in combination, can cause heat
buildup and possible tire failure.
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M+S
Winter and all-season tires.
These have better winter properties than sum-
mer tires.
Tire condition
Inspect your tires frequently for tread wear,
signs of damage and for foreign objects lodged
in the tread. Check the tread depth.
Minimum tread depth
The tread depth should not fall below 0.12 in/
3 mm. At tread depths below 0.12 in/3 mm,
there is an increased risk of high-speed hydro-
planing, even when only small amounts of water
are present on the road surface.
Winter tires display a noticeable loss in their
ability to cope with cold-weather driving condi-
tions once the tread wears to below 0.16 in/
4 mm. To ensure continued safety you should
always have such tires replaced.
Wear indicators at the tread-groove base, refer
to arrow, are distributed over the tire's circum-
ference and are marked on the side of the tire
with TWI – Tread Wear Indicator. If the tire tread
has worn down to the wear indicators, then the
legally permissible tread depth limit of 0.063 in/
1.6 mm has been reached.
Wheel/tire damage
Please note that low-profile tires, make
wheels, tires and suspension parts more
susceptible to road hazard and consequential
damages.
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Unusual vibrations encountered during normal
vehicle operation can indicate tire failure or
some other vehicle defect. This can, for exam-
ple, be caused by driving over curbs. The same
applies to any other abnormal road behavior,
such as pulling severely to the right or left.
In these cases, reduce speed immedi-
ately and have wheels and tires checked
immediately. Drive carefully to the nearest
BMW Sports Activity Vehicle Center or tire spe-
cialist. Have the vehicle towed to one of these
locations if necessary.
Tire damage can pose a potentially lethal safety
hazard for the vehicle's occupants and other
road users alike.
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New wheels and tires
Have new wheels and tires installed only
by your BMW Sports Activity Vehicle
Center or a tire shop that works according to
BMW repair procedures with correspondingly
trained personnel. If this work is not carried out
properly, there is a danger of subsequent dam-
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