Tire replacement, Tire condition – BMW 330XI User Manual

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ceed carefully to the nearest BMW cen-
ter or professional tire center, or have
the vehicle towed in to have it, its
wheels or its tires inspected.
Tire damage up to and including sud-
den and complete air loss can endan-
ger the lives of both the vehicle occu-
pants and other road users.

Tire replacement

To maintain good handling and vehicle
response, use only tires of a single
tread configuration from a single manu-
facturer.

DOT quality grades

Tread wear

Traction AA A B C

Temperature A B C

All passenger car tires must con-
form to Federal Safety Require-

ments in addition to these grades.

Tread wear

The tread wear grade is a comparative
rating based on the wear rate of the tire
when tested under controlled condi-
tions on a specified government test
course.

For example, a tire graded 150 would
wear one and one-half – 1

– times as

well on the government course as a tire
graded 100. The relative performance
of tires depends upon the actual condi-
tions of their use, however, and may
depart significantly from the norm due
to variations in driving habits, service
practices and differences in road char-
acteristics and climate.

Traction

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 speci-
fied government test surfaces of
asphalt and concrete. A tire marked C
may have poor traction.

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 charac-
teristics.

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 condi-
tions 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 tem-
perature can lead to sudden tire failure.
The grade C corresponds to a level of
performance which all passenger car

Tire condition