2004 BMW Z4 2.5I wheel

Technology for safety and driving convenience
56
Airbags
The following airbags are located under the
marked covers:
1Front airbags for driver and passenger
2Side airbags for driver and passenger
3Knee airbags for driver and passenger
Protective effect
The front airbags help protect the driver
and passenger in the event of a head-on
collision where the protection provided by
the safety belt alone would not be ade-
quate. The side airbags help provide pro-
tection in the event of a collision from the
side. Each of the side airbags is designed
to help support the seat occupant's upper
body. The knee airbags help provide addi-
tional protection in the event of a head-on
collision.
The airbags are deliberately not triggered
in every impact situation, e. g. less severe
accidents, certain roll-over conditions, or
rear-end collisions.
For information on the correct seating posi-
tion, refer to page 27.
Do not apply adhesive materials to
the cover panels of the airbags, cover
them or modify them in any other way. Do
not attempt to remove the airbag retention
system from the vehicle. Never modify or
tamper with either the wiring or the individ-
ual components in the airbag system. This
category includes the upholstery in the
center of the steering wheel, on the instru-
ment panel, the side trim panels on the
doors. Do not attempt to remove or dis-
mantle the steering wheel.
Do not touch the individual components directly after the system has been trig-
gered, because there is a danger of burns.
If you note any indication of system mal-
function, if you desire to have an airbag
deactivated, or if the airbag retention sys-
tem is triggered in response to an accident,
you should always entrust all inspection,
repair and dismantling operations to your
BMW center.
Unprofessional attempts to service the sys-
tem could lead to failure in an emergency
or undesired airbag activation, either of
which could result in personal injury.
To ensure compliance with official safety
regulations, please also entrust disposal of
airbag generators to a BMW center.<
Airbag warning information is also provided
on the sun visors.Automatic deactivation of the
passenger airbags
Before transporting a child on the
passenger seat be sure to observe
the information/instructions under Trans-
porting children safely, refer to page 33.<
Your BMW has a seat occupation detection
system. By evaluating the weight on the
passenger's seat, the system detects
whether or not the seat is occupied by a
child in the child-restraint system or an
adult.
>When a child is seated in the child-
restraint system, the front, side and
knee airbags are automatically deacti-
vated on the passenger's side.
>When an adult is traveling in the front
seat or it is unoccupied, the front, side
and knee airbags remain active on the
passenger's side.
Although not desired, it can occur in
the case of heavier children that the
passenger airbags remain active or, in the
case of very light adults or young persons,
that the passenger airbags are deactivated.
The condition of the passenger airbag sys-
tem is shown by the indicator lamp in the
central console, refer to Indicator lamps
below. If the indicator lamp signals that the
passenger airbags are active and you wish

Mobility
To ensure that you stay mobile,
the following chapter provides you with
important information on fuels and fluids,
tires and wheels, maintenance procedures
and steps to take in the event of a break-
down.

Reference
At a glance
Controls
Driving tips
Mobility
75
Wheels and tires
Tire inflation pressure
Information for your safety
It is not merely the tire's service life, but
also driving comfort and driving safety that
largely depend on the condition of the tires
and the maintenance of the specified tire
pressure.
Check tire inflation pressures regu-
larly and correct them if necessary: at
least every two weeks and before every
extended journey. If this is not done, incor-
rect tire pressures can cause driving insta-
bility or tire damage, ultimately resulting in
accidents.
Do not drive with a deflated, i.e. flat, tire
unless your vehicle is equipped with Run
Flat tires. A flat tire greatly impairs steering
and braking response, and can lead to
complete loss of control over the vehicle.<
Checking tire pressures
Check the tire inflation pressures only
when the tires are cold. This means after a
maximum driving distance of 1.25 miles/
2 km or if the vehicle has been parked for at
least 2 hours. Warm tires have higher infla-
tion pressures.
Reinitialize the Flat Tire Monitor after cor-
recting the tire inflation pressure. Refer to
page 55.
Inflation pressures for original tires
The specified inflation pressures for tires at
ambient temperature are provided on the
placard on the B-pillar and are visible when
the driver's door is open.
Inflation pressures for other tire
sizes
The following tire inflation pressure tables
show the inflation pressures for the speci-
fied tire sizes at ambient temperature.
Reinitialize the Flat Tire Monitor after
correcting the tire inflation pressure.
Refer to page 55.<
Tire size
The inflation pressures in the table apply to
BMW-approved tire sizes and brands. Your
BMW center will be glad to supply this
information.

Wheels and tires
76
Z4 2.5i
Z4 3.0i
TiresPressure specifications in psi/kPa
Tires
All pressure specifications in the table are
indicated in psi/kilopascal with cold tires,
cold = ambient temperature
225/50 R 16 92 V
225/45 R 17 91 W30/210 33/230
225/40 R 18 88 W 30/210 –
245/40 R 17 91 W
255/35 R 18 90 W–33/230
All winter tires 30/210 33/230
You will find more information about permissible loads and weights on page 101.
TiresPressure specifications in psi/kPa
Tires
All pressure specifications in the table are
indicated in psi/kilopascal with cold tires,
cold = ambient temperature
225/45 R 17 91 W 33/230 36/250
225/40 R 18 88 W 33/230 –
245/40 R 17 91 W
255/35 R 18 90 W–36/250
All winter tires 33/230 36/250
You will find more information about permissible loads and weights on page 101.

Wheels and tires
78
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 con-
trolled conditions on a specified indoor lab-
oratory 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, under-inflation, or excessive load-
ing, either separately or in combination,
can cause heat buildup and possible tire
failure.<
RSC: Run Flat tires
Run Flat tires are labeled on the sidewall
with a circular symbol containing the letters
RSC. Refer to page 80.
M+S
Winter and all-season tires.
These have better winter performance
properties than summer tires.
Tire condition
Inspect your tires frequently for tread wear,
signs of damage and for foreign objects
lodged in the tread. Check the tread depth.
Tire tread
Tread depth should not be allowed to go
below 1/8 in/3 mm even though in Europe,
for example, the legally specified minimum
tread depth is only 1/16 in/1.6 mm. Below
1/8 in/3 mm tread depth, there is a very
high risk of hydroplaning, even at relatively moderate speeds and with only small
amounts of water on the road.
At tread depths below approx. 1/6 in/
4 mm, winter tires display a perceptible
decrease in their ability to cope with winter
driving conditions, and should be replaced
in the interest of safety.
Tread wear indicators in the tread-groove
base, see arrow, are distributed around the
wheel circumference and are labeled on
the tire sidewall as TWI, Tread Wear Indica-
tor. At a tread depth of 1/16 in/1.6 mm, the
indicators signal that the legally permissi-
ble wear limit has been reached.
Tire damage
Unusual vibrations encountered dur-
ing normal vehicle operation can indi-
cate tire failure or some other vehicle mal-
function. This type of problem can be
caused by contact with curbs, etc. This is
also true for irregularities in the vehicle's
handling characteristics, such as a pro-
nounced tendency to pull to the left or right.
Should this occur, respond by immediately
reducing your speed. Proceed carefully to
the nearest BMW center or professional tire
center, or have the vehicle towed there to
have it and its wheels or tires inspected.
Tire damage up to and including sudden
and complete air loss can pose an extreme
hazard for both vehicle occupants and
other road users.<

Reference
At a glance
Controls
Driving tips
Mobility
79
Wheel and tire replacement
Unprofessional attempts by laymen to
service tires can lead to damage and
accidents.
Have this work performed by skilled pro-
fessionals only. Any BMW center has the
required technical knowledge and the
proper equipment and will be happy to
assist you.<
The correct wheel and tire combination
also affects various systems that would
otherwise be impaired, for example ABS or
DSC.
Have the wheels balanced after each tire or
wheel replacement.
BMW advises against using retreaded
tires, since driving safety may be
impaired. This is due to possible variations
in casing structures and, in some cases, to
their extreme age, factors which can lead
to a decrease in their durability.<
The correct wheels and tires
BMW recommends using only wheels
and tires that have been tested and
approved by BMW for your particular vehi-
cle model, as otherwise body contact and
serious accidents can result despite the
use of the same nominal size, e.g. due to
manufacturing tolerances. If non-approved
wheels and tires are used, BMW cannot
evaluate their suitability, and therefore can-
not be held liable for driving safety.<
To maintain good handling and vehicle
response, use only tires of a single brand
and tread configuration. In the event of a
flat tire, remount the previous wheel and
tire combination as soon as possible.
Recommended tire sizes and brands
BMW tests certain tire brands for each tire
size, classifies them as road-safe and
approves them. You can best find out
about these at a specialized shop, particu-
larly your BMW center. Observe any coun-
try-specific regulations, e.g. on making a
corresponding entry in the vehicle docu-
ments.The factory-approved radial-ply tires are
matched to your vehicle and have been
selected to provide optimum safety and
driving comfort when used properly.
Run Flat tires fitted
Use only Run Flat tires, since no spare
wheel is available in the event of a flat.
Special characteristics of winter
tires
BMW recommends the use of winter tires
for operation under winter road conditions.
While all-season tires, with M+S designa-
tion, provide better winter traction than
summer tires, they generally do not achieve
the full performance of winter tires.
For mounting winter tires, refer to the
descriptions under Tire condition and
Wheel and tire replacement, pages 78, 79.
Run Flat tires fitted
Use only winter Run Flat tires, since no
spare wheel is available in the event of a
flat.
Observing speed ratings
Never exceed the maximum speed for
which the winter tires are rated.
Unprofessional attempts by laymen to ser-
vice tires can lead to damage and acci-
dents. Have this work performed by skilled
professionals only. The technicans at your
BMW center will be glad to assist you with
the required professional knowledge and
specialized equipment.<
Storage
Store tires in a cool, dry place, protecting
them against light whenever possible. Pro-
tect the tires from contact with oil, grease
and fuel. Do not exceed the maximum tire
inflation pressures specified on the tire
sidewall.

Wheels and tires
80
Run Flat tires
Run Flat tires are labeled on the sidewall
with a circular symbol containing the letters
RSC. Run Flat tires consist of self-support-
ing tires and special rims. The tire rein-
forcement ensures that driving remains
possible to a restricted degree in the event
of pressure drop or even if the tire is
deflated.
When mounting or replacing summer
tires with winter tires, or vice versa,
use Run Flat tires since no spare wheel is
available in the event of a flat. Your BMW
center knows how to work with Run Flat
tires and is equipped with the necessary
special tools.<
Driving with a damaged tire
When using Run Flat tires, you can con-
tinue driving cautiously at a maximum
speed of 50 mph / 80 km/h, depending on
the cargo load and the extent of tire dam-
age.
If there is a total loss of tire inflation pres-
sure, 0 psi/kilopascal, or obvious tire dam-
age, you can gauge the mileage for contin-
ued driving on the basis of the following
indications:
>With a light load:
1 person without luggage:
approx. 150 miles/250 km
>With a medium load:
1 person, luggage compartment full,
or
2 persons without luggage:
approx. 90 miles/150 km>With a full load:
2 persons, luggage compartment full:
approx. 30 miles/50 km
Drive cautiously. Do not exceed a
speed of 50 mph / 80 km/h. Be aware
that vehicle handling will be altered when
there is a loss in inflation pressure. Antici-
pate, e.g., reduced tracking during braking,
longer braking distances and changed
steering characteristics.
For safety reasons, BMW recommends not
to have Run Flat tires repaired if they are
damaged, but to consult your BMW center
in such cases.<
Snow chains*
Only certain types of snow chains have
been tested by BMW, classified as road-
safe and approved. Consult your BMW
center for more information. BMW recom-
mends using only approved fine-link snow
chains. Use them in pairs on either summer
or winter tires, but only on both rear
wheels.
Comply with all manufacturer's safety pre-
cautions when mounting the chains.
Do not exceed a speed of 30 mph /
50 km/h when using snow chains.
Do not initialize the Flat Tire Monitor
after snow chains have been
mounted.
When driving with snow chains, it may be
useful to deactivate the DSC briefly. Refer
to page 53.<

Replacement procedures
88
Replacement procedures
Onboard tool kit
The onboard tool kit is stored in a tool
pouch. It is located in the luggage compart-
ment beneath the floor panel.
Windshield wiper blades
1.Fold the wiper arm completely out from
the windshield
2.Position the wiper blade at an angle and
pull the release spring, see arrow
3.Fold the wiper blade down and unhook
it toward the windshield
4.Pull the wiper blade past the wiper arm
toward the top
5.Insert a new wiper blade and apply
pressure until you hear it engage.
Lamps and bulbs
The lamps and bulbs make essential contri-
butions to the safety of your vehicle. There-
fore, comply fully with the following instruc-
tions during bulb replacement. If you are
not familiar with the procedures, BMW rec-
ommends that you have your BMW center
carry out the work.
Do not touch the glass portion of
a new bulb with your bare hands
since even small amounts of impurities
burn in to the surface and reduce the ser-
vice life of the bulb. Use a clean cloth,
paper napkin or a similar material, or hold
the bulb by its metallic base.<
A replacement bulb set is available from
your BMW center.
Before working on the electrical sys-
tem, switch off the electrical acces-
sory you are working on or disconnect the
cable from the negative terminal of the bat-
tery. Failure to observe this precaution
could result in short circuits.
To prevent injuries and damage, always
comply with any instructions provided by
the bulb manufacturer.<
Accessing the headlamps
Protective cover in the wheel well
To gain access to the headlamp covers,
turn the front wheels in the required direc-
tion.