tire type BMW CONVERTIBLE 1998 Owners Manual

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At a glanceControlsCar careRepairsTechnicalDataIndex
ABS enhances active safety by helping
to prevent the wheels from locking under
braking. 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
uncontrolled oversteer.
ABS is designed to meet two essential
requirements during every application:
dto help provide vehicle stability on all
types of road surface (asphalt,
cement, dirt, moisture, snow and ice).
dto help to retain steering and maneu-
vering capability under the same con-
ditions.
However, certain important consider-
ations must be borne in mind in connec-
tion with these requirements:
Not even ABS can suspend the normal
laws of physics. ABS alone can not pre-
vent accidents when the brakes are
applied without an adequate safety
interval between vehicles, when the car
reaches excessive rates of lateral accel-
eration in curves, or if aquaplaning
occurs. Responsibility for these types of
situations remains in the hands (and 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.
Driving with ABSThe yellow ABS warning in the instru-
ment panel goes out as soon as the
engine is started.
The system becomes operative once the
vehicle exceeds a speed of 5 mph
(8 km/h). The ABS is deactivated when-
ever the vehicle's speed drops below
approx. 2 mph (3 km/h). This means that
the wheels can lock in the Þnal phase of
a braking action - a factor of no signiÞ-
cance in actual practice.
The ABS system closed-loop control cir-
cuit cycles in fractions of a second. A
pulsation at the brake pedal indicates to
the driver that ABS is active, that is, that
the car is within its maximum braking
range. In addition, the audible pulsation
that accompanies the control operation
calls your attention to the reduced trac-
tion between tires and road surface
(marginal adhesion), and reminds you
that the vehicle's speed should be
reduced to adapt to road conditions.On road surfaces featuring a loose top
layer on a Þrmer substratum, e.g., on
gravel or snow, the braking distances
with ABS may be longer than with the
wheels locked. However, ABS continues
to provide enhanced vehicle and steer-
ing control under these conditions.
a
To ensure that the system remains
completely operational, never modify the
ABS. Service procedures on ABS are to
be performed by authorized technicians
only.c
ABS may fail to function with maximum
efÞciency when tires of different sizes
are mounted (e.g., winter tires/spare tire;
remount the correct tires at all wheels as
soon as possible).
In the event of a fault, the ABS warning
lamp in the instrument cluster lights up,
refer to page 18. The braking system
then reverts to conventional operation as
on a vehicle without ABS. However,
have the brake system checked by your
BMW Retailer as soon as possible. To
prevent undetected defects and cumu-
lative faults from adversely affecting the
brake system, refer any problems to
your authorized BMW Retailer at the
earliest opportunity.
Antilock Brake System (ABS)

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At a glanceControlsCar careRepairsTechnicalDataIndex
Tires and wheelsUse only BMW-approved tires.
Due to the high speeds which this vehi-
cle can reach, the use of specific
brands, specifications and dimensions
is mandatory. Consult any BMW
Retailer for details.
Observe national, provincial and state
regulations.
The tire codes will aid you in selecting
the correct tire. The essential data for
radial tires are as follows:The speed rating indicates the
approved 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 149 mph (240 km/h)
W = up to 167 mph (270 km/h)
ZR = over 149 mph (240 km/h)
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)
Use screw-on valve stem caps to
protect the tire valves against dirt. Dirt
in the valves frequently leads to slow
leaks.Example:Nominal width
in mm
Aspect ratio in %
Type of radial-code
letter for radial
Rim diameter in inches
Load rating
(not on ZR tires)
Speed rating
(before R on ZR tires)
205/60 R 15 91 H
Codes on steel/light-alloy wheels:
7 J x 15 H 2
Hump width (inches)
Code letter for
flange type
Denotes
drop-center rim
Rim diameter (inches)
Hump of 2 rim shoulders
The right choice

13 2
Exterior finishTo provide effective corrosion protec-
tion, multilayer paintwork is applied at
the factory. Cataphoretic immersion
priming techniques are supplemented
using special body-cavity protectants,
with the application of specially-devel-
oped and extensively tested materials.
The entire underbody is sprayed with a
flexible PVC layer before final compre-
hensive application of a wax-based
protectant.
Regular maintenance makes an impor-
tant contribution to maintaining the
safety and value of your vehicle.
Increasing awareness of the effects of
harmful environmental factors on vehi-
cle finishes have led paint and vehicle
manufacturers to initiate ongoing pro-
grams designed to further improve the
durability of their finishes. Despite the
high quality of the resulting products,
local and regional factors can still have
a negative effect on your car's paint-
work. These should guide you in deter-
mining the frequency and extent of your
efforts to maintain the vehicle finish.
Depending upon material and type of
impact (perforation of paint layer), phys-
ical stresses from sand, road salt,
gravel, etc. can cause corrosion to start extending beneath the finish, starting at
the point of impact.
Road dirt, tar spots, dead insects, ani-
mal droppings (strong alkali effect) and
tree excretions (resins and pollen) all
contain substances capable of causing
damage when allowed to remain on
your car's finish for any period of time
(spots, etching, flaking, separation in
the top coat).
In industrial areas, deposits from ßy ash,
lime, oily soot, sulphur dioxide in pre-
cipitation (acid rain) and other environ-
mental pollutants will damage the car's
surface (usually limited to the external
horizontal surfaces) unless adequate
protection is provided.
In coastal regions, high levels of atmo-
spheric salt and humidity promote cor-
rosion.
In tropical zones, temperatures of over
100 5F (approx. 406) in the shade pre-
vail, in addition to heavy ultraviolet radi-
ation and high humidity. Under those
circumstances, light-colored paints
reach temperatures of up to 175 5F
(approx. 806) and dark paints up to
250 5F (approx. 1206).
Caring for the vehicle finishAs a precaution against damage result-
ing from exposure to aggressive sub-
stances, we recommend that you wash
the car weekly when it is used in an
area with high levels of air pollution or
aggressive natural substances (tree
resin, pollen).
Remove particularly aggressive sub-
stances immediately in order to prevent
changes to, and discoloration of, the
paint. Such substances are e.g., gaso-
line spilled during refueling, oil, grease,
brake fluid and bird droppings.
Any contamination remaining on the
surface of the vehicle will be especially
conspicuous after washing. Use clean-
ing fluid or alcohol with a clean cloth or
cotton pad to remove. You can use tar
remover to remove any spots on the fin-
ish of the vehicle, but should never
apply it or any other aggressive
cleanser to lenses or headlamp covers.
These areas should then be waxed to
maintain protection.b
A full range of car-care products is
available from your BMW Retailer.c
Caring for your car