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112n
To maintain good handling and vehicle
response, use only tires of a single
tread configuration from a single manu-
facturer. BMW tests and approves
wheel/tire combinations. Refer to
page 116.
DOT Quality Grades Treadwear
Traction AA A B C
Temperature A B C
All passenger vehicle tires must
conform to Federal Safety
Requirements in addition to these
grades.< Tread wearThe 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 g) 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.
TractionThe 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 performance.
The traction grade assigned to
this tire is based on straight-
ahead braking traction tests, and does
not include acceleration, cornering,
aquaplaning, or peak traction charac-
teristics.< TemperatureThe temperature grades are A (the
highest), B, and C, representing the
tireÕs 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
temperature can lead to sudden tire
failure. The grade C corresponds to a
level of performance which all
passenger vehicle tires must meet
under the Federal Motor Vehicle Safety
Standard No. 109. Grades B and A
represent 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 loading, either separately or
in combination, can cause heat buildup
and possible tire failure.<< < <
Uniform Tire Quality Grading Quality grades can be found where
applicable on the tire sidewall between
tread shoulder and maximum section
width. For example:
Tread wear 200 Traction AA
Temperature A
Do not use retreaded tires, since
driving safety may be impaired by
their use. This is due to the possible
variations in casing structures and, in
some cases, to their extreme age,
factors that can lead to a decrease in
their durability.<
Tire replacement
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115n
IndexDataTechnologyRepairsCar careControlsOverview
Winter tires Snow chainsChoosing the right tire BMW recommends winter tires (M+S
radial tires) for operation under inclem-
ent winter driving conditions. While
so-called all season tires (M+S desig-
nation) provide better winter traction
than summer tires with the load ratings
H, V, W, Y and ZR, they generally do
not achieve the performance of winter
tires.
In the interests of safe tracking and
steering response, install radial tires
made by the same manufacturer and
with the same tread configuration on all
four wheels if you elect to mount winter
tires. Do not exceed specified
maximum speedsIn Germany: attach a corresponding
sign in accordance with the Federal
Motor Vehicles Safety Standards in
your field of vision if the maximum
speed of the vehicle is higher. This
sticker is available from the tire dealer
or your BMW center. Never exceed the maximum speed
for which the tires are rated.
Unprofessional attempts by laymen to
service tires can lead to damage and
accidents.
Have this work performed by skilled
professionals only. Your BMW center
will be glad to assist you with both their
expertise and the proper equipment for
your vehicle.<
Tire condition, tire pressureWinter tires display a perceptible loss in
their ability to cope with winter driving
conditions once the tread wears to
below 0.16 in (4 mm), and should thus
be replaced.
Comply with the specified tire inflation
pressure and be sure to have the
wheels balanced each time a tire or
wheel is changed. In addition, also have
the Tire Pressure Warning (RDW) reini-
tialized, for details refer to page 78.
The use of narrow-link BMW snow
chains on winter tires is approved only
in pairs and only on the rear wheels.
Comply with all manufacturer's safety
precautions when mounting the chains.
Deactivate the Tire Pressure
Warning (RDW) when using snow
chains. The snow chains can lead to
malfunction warnings and undetected
losses in pressure.
For further information, refer to
page 78.<
Page 159 of 183

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IndexDataTechnologyRepairsCar careControlsOverview
The limitations inherent to radio recep-
tion in a moving vehicle have been
minimized by a number of innovative
system designs:
The "Radio Data System" (RDS) makes
sure that, for broadcast stations
sending on several frequencies, the
radio automatically tunes to the
frequency with the best reception
quality.
The Diversity Antenna system employs
several FM antennas integrated within
the rear window to provide three sepa-
rate sources for receiving broadcast
waves. An integral processor automati-
cally selects the antenna with the best
FM reception quality at any given time.
The selection of the antenna takes
place within milliseconds, and is there-
fore not noticed by the radio listener. The primary goal in developing the
Dynamic Stability Control (DSC) for the
BMW M3 is to achieve the greatest
amount of safety while at the same time
getting the most pleasure out of perfor-
mance-oriented driving.
Using highly sensitive sensors, the DSC
monitors current operating conditions
for your vehicle as they relate to driving
stability and traction. In addition, wheel
speeds, steering angle, lateral acceler-
ation, brake pressure and vehicle
movement around its vertical axis are
also ascertained and evaluated.
If the DSC detects unstable conditions
on a curve, then the DSC will intervene
in engine management within millisec-
onds, reducing drive torque or, if the
need arises, will individually slow one or
more wheels down to keep the vehicle
on a steady course.
If differences in wheel speed should
occur, the system will recognize the
dangers associated with wheel spin
and will reduce the drive torque; if
necessary, it will do so using brake
intervention at the rear wheels as well.
DSC offers the highest degree of
driving stability and safety not only
when you first start your vehicle, are
driving on straightaways or when
braking, but also when driving through
curves.The safety belt tensioner makes sure
that the belt tightens during a head-on
collision to ensure that occupants
remain firmly positioned in their seats.
A gas-pressure system retracts the
buckle assembly to tension the
shoulder and lap belts within fractions
of a second. This reduces the tendency
to slide under the lap belt. Radio reception DSC Safety belt tensioner