Tire Condition - BMW SERIE 7 2005 Owner's Manual

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 con-
trolled conditions on a specified indoor lab-
oratory 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.<
RSC: 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 192.
M+S
Winter and all-season tires.
These have better winter properties than
summer tires.

Tire condition

Inspect your tires frequently for treadwear,
signs of damage and for foreign objects
lodged in the tread. Check the tread depth.
Tire tread
The tread depth should not drop below
ε in/3 mm, although, for example, Euro-
pean legislation only specifies a minimum
tread depth of κ/ΦΚ in/1.6 mm. At tread
depths below ε in/3 mm, there is an
increased risk of high-speed hydroplaning,
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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 κ/Κ 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
κ/ΦΚ in/1.6 mm that the legally permitted
wear limit has been reached.
Wheel/tire damage
Due to low-profile tires, please note
that wheels, tires and suspension
parts are more susceptible to road hazard
and consequential damages.
Unusual vibrations encountered during
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.
In these cases reduce speed immediately.
Drive carefully to the next BMW center or
tire dealer, or have the vehicle towed to one
of these locations if necessary.
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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