BMW 745LI Manual Do Utilizador

 187

wear one and one-half – 1 g – times as 
well on the government course as a tire 
graded 100. The relative performance of 
tires depends upon the actual conditions of 
their use, however, and may depart signifi-
cantly from the norm due to variations in 
driving habits, service practices and differ-
ences in road characteristics and climate.

The traction grades, from highest to lowest, 
are AA, A, B, and C. 
Those grades represent the tire's ability to 
stop on wet pavement as measured under 
controlled conditions on specified govern-
ment test surfaces of asphalt and concrete. 
A tire marked C may have poor traction 
performance.

The traction grade assigned to this 
tire is based on straight-ahead 

braking traction tests, and does not include 
acceleration, cornering, hydroplaning, or 
peak traction characteristics.

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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 
loading, either separately or in combina-
tion, can cause heat buildup and possible 
tire failure.

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Quality grades can be found where appli-
cable on the tire sidewall between tread 
shoulder and maximum section width. For 
example:

Treadwear 200 Traction AA 
Temperature A 

Do not use retreaded tires, since dri-
ving safety may be impaired. Possible 

variations in the design and the age  – which 
could be substantial – of the carcasses can 
lead to unusually rapid wear.

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The tire's date of manufacture is indicated 
on the sidewall: 
DOT ... 3402 indicates that a tire was 
manufactured in week 34 of the year 2002. 

Regardless of mileage or wear, BMW 
recommends that you replace all tires – 
including the spare – after a maximum of 
6 years,  even though the tires may have a 
theoretical service life of up to 10 years. 

Use only wheel and tire combinations 
that BMW has approved for your par-

ticular vehicle. Variations in factors such as 
manufacturing tolerances mean that even 
wheels and tires with identical official size 
ratings could actually have different dimen-
sions than the approved units – these diffe-
rences could lead to body contact, and 
with it the risk of severe accidents. If non-
approved wheels and tires are used, BMW 
cannot evaluate their suitability, and there-
fore cannot be held liable for driving 
safety.

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BMW tests certain tire brands for each tire 
size, classifies them as road-safe and 
approves them. Consult your BMW center 
for more information. Observe any country-
specific regulations, e.g. on making a cor-
responding entry in the vehicle documents.

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