BMW 2004 645Ci Convertible Manual Do Proprietário

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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 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.
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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 
.
M+S 
Winter and all-season tires.
These have better winter properties than 
summer tires.
Tire condition 
Before driving off, inspect your tires for 
tread wear, signs of damage and foreign 
objects lodged in the tread, and check the 
tread depth.
Minimum tread depth 
The tread depth should not drop below 
0.12 in/3 mm, although, for example, Euro-
pean legislation only specifies a minimum 
tread depth of 0.063 in/1.6 mm. At tread 
depths below 0.12 in/3 mm there is an 
increased risk of high-speed hydroplaning, 
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 0.157 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 
0.063 in/1.6 mm that the legal wear limit 
has been reached. The tread is then no 
longer visible at these points.
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, immediately reduce speed. 
Drive cautiously to the nearest BMW center 
or tire dealer or, if necessary, have the 
vehicle towed there.
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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Online Edition for Part No. 01 41 0 157 980 - © 01/04 BMW AG