tire type BMW 328Ci COUPE 2000 E46 Owner's Manual

Page 108 of 189

106n
Antilock Brake System (ABS)The concept ABS enhances active safety by helping
to prevent the wheels from locking dur-
ing brake applications. Locked wheels
are dangerous. When the front wheels
slide, the driver loses steering control
over the vehicle. Traction loss at the
rear wheels can cause the rear end to
break into an uncontrolled skid.
The system can achieve the shortest
braking distances possible under most
conditions (on straight-aways and in
curves, on asphalt, ice, wet road sur-
faces, etc.).
ABS is designed to meet two essential
requirements during every brake appli-
cation:
>To help provide vehicle stability
>To help maintain steering control and
maneuverability – on all types of road
surfaces (asphalt, concrete, mud,
wet, snow, ice).
Braking with ABSThe system becomes operative once
the vehicle exceeds a speed of approx.
6 mph (10 km/h). Below approx. 3 mph
(6 km/h), it is once again deactivated.
This means that the wheels can lock in
the final phase of a panic stop – a factor
of no significance in actual use.
If you are in a situation that requires full
braking, you will exploit the full benefits
of the ABS system if you apply maxi-
mum brake pressure ("panic stop").
Since the vehicle maintains steering re-
sponsiveness, you can avoid possible
obstacles with a minimum of steering
effort, despite the full brake application.
The ABS system closed-loop control
circuit cycles in fractions of a second.
A pulsation at the brake pedal indicates
to the driver that ABS is active, that is,
that the vehicle is within its maximum
braking range. In addition, a pulsation –
a result of the control function cycles –
indicates to the driver that vehicle
speed should be reduced to adapt to
road surface conditions when there is
reduced traction and grip between tires
and road surface (slippery road sur-
face).
In driving conditions where there is a
loose upper surface together with a
subsurface that provides good traction (on gravel or snow, for instance), or with
snow chains, the braking distance may
also be longer than when the wheels
are locked. However, ABS continues to
provide enhanced vehicle stability and
steering response under these condi-
tions.
Information for your safetyNot even ABS can suspend the laws
of physics. ABS cannot prevent the
consequences of brake applications
with inadequate clearances for safety
between vehicles, when exceeding the
speed limit in curves, or the risks in-
volved when aquaplaning occurs. Re-
sponsibility for these types of situations
remains in the hands (and at the feet) of
the driver.
You should never allow the added
safety of ABS to lull you into a false
sense of security, or mislead you into
taking increased risks that could affect
your own safety and that of others.
Do not make any modifications to
the ABS system.
Service procedures on ABS are to be
performed by authorized technicians
only.<

Page 117 of 189

115n
RepairsIndexOverview Controls Car care Technology Data
Wheel and tire combinations The right choice Use only BMW-approved tires, refer to
page 117.
Due to the high speeds this vehicle can
achieve, the use of specific tire brands,
specifications and dimensions is man-
datory.
Consult any BMW center for details.
Comply with local/national regulations.
The correct wheel/tire combinaton
affects different sytems, such as
ABS, ATC, DSC. The function of these
systems can be impaired if the correct
combinaton is not used.
Therefore, only use tires of the same
brand and tread pattern. Replace a flat
tire with an approved wheel/tire combi-
nation as soon as possible.<
Codes on the tires and wheels The tire codes will aid you in selecting
the correct tire.
Codes on radial tires:
The speed rating indicates the ap-
proved maximum speed for the tire.
Summer tires:
S = up to 112 mph (180 km/h)
T = up to 118 mph (190 km/h)
H = up to 130 mph (210 km/h)
V = up to 150 mph (240 km/h)
W = up to 167 mph (270 km/h)
Y = above 167 mph (270 km/h)
ZR = above 150 mph (240 km/h) Example:
Nominal width
in mm
Aspect ratio in %
Radial tire code
Rim diameter in inches
Load rating
(not on ZR tires)
Speed rating
(before R on ZR tires)
225/50 R
1692W
Winter tires:
Q M+S = up to 100 mph (160 km/h)
T M+S = up to 118 mph (190 km/h)
H M+S = up to 130 mph (210 km/h)
Codes stamped on light-alloy wheels:
Protect valve inserts against dirt using
screw-on valve stem caps. Dirt in the
valves frequently leads to slow leaks. Example:
Rim width
in inches
Code letter for
flange type
Symbol for full-drop
center rim
Rim diameter in inches
Hump on the 2 rim shoulders
7 x 16 H 2
J