Tire condition – BMW 745i Sedan 2004 User Manual
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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 tires must meet
under the Federal Motor Vehicle Safety
Standard No. 109. Grades B and A repre-
sent 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 load-
ing, either separately or in combination,
can cause heat buildup and possible tire
failure.
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Run-flat tires
You will recognize run-flat tires by a circular
symbol containing the letters RSC on the
side of the tire, refer to page
.
M+S
Winter and all-season tires.
These have better winter properties than
summer 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.
Tire tread
The tread depth should not fall below e in/
3 mm.
At tread depths below e in/3 mm, there is
an increased risk of high-speed hydroplan-
ing, even when only small amounts of
water are present on the road surface.
As winter tires display a noticeable loss in
their ability to cope with cold-weather driv-
ing conditions once the tread wears to
below k/K 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
circumference and are marked on the side
of the tire with TWI – Tread Wear Indicator.
These indicators signal at a tread depth
of k/FK in/1.6 mm that the legally permitted
wear limit has been reached.
Tire damage
Unusual vibrations encountered dur-
ing normal vehicle operation can
indicate tire failure or some other vehicle
defect. This can, for example, be caused
by driving over curbs.
These kinds of problems may also be
signaled by other changes in vehicle
response, such as a strong tendency to
pull to the left or right. Should this occur,
respond by immediately reducing your
speed. Carefully proceed – or have your
vehicle towed – to the nearest BMW 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 occupants and
other road users alike.
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