BMW 2004 Z4 Roadster 2.5i Manual Do Proprietário

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Wheels and tires
78
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, under-inflation, 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
Run Flat tires are labeled on the sidewall 
with a circular symbol containing the letters 
RSC. Refer to page 
.
M+S
Winter and all-season tires.
These have better winter performance 
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 
Tread depth should not be allowed to go 
below 1/8 in/3 mm even though in Europe, 
for example, the legally specified minimum 
tread depth is only 1/16 in/1.6 mm. Below 
1/8 in/3 mm tread depth, there is a very 
high risk of hydroplaning, even at relatively 
moderate speeds and with only small 
amounts of water on the road.
At tread depths below approx. 1/6 in/
4 mm, winter tires display a perceptible 
decrease in their ability to cope with winter 
driving conditions, and should be replaced 
in the interest of safety.
Tread wear indicators in the tread-groove 
base, see arrow, are distributed around the 
wheel circumference and are labeled on 
the tire sidewall as TWI, Tread Wear Indica-
tor. At a tread depth of 1/16 in/1.6 mm, the 
indicators signal that the legally permissi-
ble wear limit has been reached.
Tire damage 
Unusual vibrations encountered dur-
ing normal vehicle operation can indi-
cate tire failure or some other vehicle mal-
function. This type of problem can be 
caused by contact with curbs, etc. This is 
also true for irregularities in the vehicle's 
handling characteristics, such as a pro-
nounced tendency to pull to the left or right. 
Should this occur, respond by immediately 
reducing your speed. Proceed carefully to 
the nearest BMW center or professional tire 
center, or have the vehicle towed there to 
have it and its wheels or tires inspected.  
Tire damage up to and including sudden 
and complete air loss can pose an extreme 
hazard for both vehicle occupants and 
other road users.
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