2006 BMW Z4 3.0SI ROADSTER wheel size

Wheels and tires
80
Wheels and tires
Tire inflation pressure
Information for your safety
It is not merely the tire's service life, but also
driving safety and driving comfort that largely
depend on the condition of the tires and the
maintenance of the specified tire pressure.
Check tire inflation pressures regularly
and correct them if necessary: at least
every two weeks and before every extended
journey. If you fail to observe this precaution
you may be driving on tires with incorrect tire
pressures, a condition that can not only com-
promise your vehicle's driving stability, but also
lead to tire damage and the risk of an accident.
Do not drive with deflated, i.e. flat tires, except
when using Run-Flat Tires. A flat tire will seri-
ously impair your vehicle's handling and braking
response. Attempts to drive on a flat tire can
lead to loss of control over the vehicle.<
Checking pressure
Check the tire inflation pressures only when the
tires are cold. This means after a maximum of
1.25 miles/2 km driving or when the vehicle has
been parked for at least 2 hours. Warm tires
have higher inflation pressures.
Inflation pressure specifications
The specified inflation pressures for your stan-
dard tires are provided on the placard on the
B-pillar and are visible when the driver's door is
open.Reinitialize the Flat Tire Monitor after cor-
recting the tire inflation pressure. Refer to
page51.<
The following tire inflation pressure tables show
the inflation pressures for the specified tire
sizes at ambient temperature.
The inflation pressures in the table apply
to BMW-approved tire sizes and recom-
mended tire brands. Your BMW Center will be
glad to supply this information.<
To determine the correct tire inflation pressure
for your tires, refer to the following tables.
Tire size
The inflation pressures in the table apply to
BMW-approved tire sizes and recommended
tire brands. Your BMW Center will be glad to
supply this information.

Wheels and tires
82
Z4 Coupe 3.0si
Tire coding
Understanding the lettering on the tire sidewall
makes it easier to identify and choose the cor-
rect tires.
Tire size
Speed code letter
Q = up to 100mph or 160km/h
T = up to 118mph or 190km/h
H = up to 131mph or 210km/h
V = up to 150mph or 240km/h
W = up to 167mph or 270km/h
Y = up to 186mph or 300km/h
Tire Identification Number
Tires with DOT codes meet the guidelines of
the U.S. Department of Transportation.DOT code:
Tire age
The date on which the tire was manufactured is
indicated by the code on the sidewall:
DOT … 5005 indicates that the tire was manu-
factured in week 50 of the year 2005.
BMW recommends the replacement of all tires
every 6 years at the latest, even if a tire usage of
10 years is possible.
Uniform Tire Quality Grading
Quality grades can be found where applicable
on the tire sidewall between tread shoulder and
maximum section width. For example:
Treadwear 200 Traction AA
Temperature A
DOT Quality Grades
Tread wear
Traction AA A B C
Temperature A B C
Tire sizePressure specifications in psi/kPa
All pressure specifications in the table are
indicated in psi/kilopascal with cold tires,
cold = ambient temperature
225/45 R 17 91 W
225/45 R 17 91 H/V M+S33/230 39/270
Front: 225/45 R 17 91W
Rear: 255/40 R 17 94 W33/230
––
39/270
Front: 225/40 R 18 88 W
Rear: 255/35 R 18 90 W33/230
––
39/270
You will find more information about permissible loads and weights on page109.
e.g.
Nominal width in mm
Aspect ratio in Ξ
Radial belt construction
Rim diameter in inches
Load rating,
not on ZR tires
Speed code letter, in
front of the R on ZR tires225/50 R1692 V
e.g.
Manufacturer's code
for tire make
Tire size and
tire design
Tire ageDOT xxxx xxx 5005

Wheels and tires
84 the letters TWI, for Tread Wear Indicator, on the
tire's sidewalls identify tires that incorporate
these wear indicators. Once the tire tread has
worn down to the wear indicators, the tire has
worn to a depth of 1/16 in/1.6 mm.
Wheel/tire damage
Due to low-profile tires, please note that
wheels, tires and suspension parts are
more susceptible to road hazards and conse-
quential damages.<
Unusual vibrations encountered during normal
vehicle operation can indicate tire failure or
some other vehicle malfunction. This can, for
example, be caused by driving over curbs. The
same applies to any other abnormal road
behavior, such as pulling severely to the right or
left.
In these cases, reduce speed immedi-
ately and have wheels and tires thor-
oughly checked. To do so, drive carefully to the
nearest BMW Center or tire shop that works
according to BMW repair procedures with cor-
respondingly trained personnel. If necessary,
have the vehicle towed there.
Tire damage can be extremely dangerous for
vehicle occupants and other road users.<
Tire age
For various reasons, such as the development
of brittleness, BMW recommends tire replace-
ment after no more than 6 years, regardless of
the actual wear of the tires.
The date on which the tire was manufactured is
indicated by the code on the sidewall:
DOT … 5005 indicates that the tire was manu-
factured in week 50 of the year 2005.
Run-Flat Tires
The symbol identifying Run-Flat Tires is a circle
with the letters RSC on the sidewall.
Run-Flat Tires comprise a conditionally self-
supporting tire and a special rim. The reinforce-
ment in the sidewalls ensures that the tire can
continue to be used subject to certain restric-
tions, even if depressurized.
For information on continuing to drive with a flat
tire, refer to Flat tire warning on page51.
Wheel and tire replacement
Have new wheels and tires installed only
by your BMW Center or tire shop that
works according to BMW repair procedures
with correspondingly trained personnel. Work
that is improperly carried out could result in
consequential damage and pose safety haz-
ards. Make sure that the new wheels are bal-
anced.<
Retreaded tires
BMW advises against using retreaded
tires, since driving safety may be
impaired. The causes for this include potentially
different tire casing structures and often wide
variations in tire age, which can result in a lim-
ited service life.<
Correct wheels and tires
BMW recommends using only wheels
and tires that have been approved by
BMW for your particular vehicle model, other-
wise body contact and serious accidents can
result despite the use of the same nominal size,
e.g. due to manufacturing tolerances. If non-

Reference
At a glance
Controls
Driving tips
Mobility
85
approved wheels and tires are used, BMW can-
not evaluate their suitability, and therefore can-
not be held liable for driving safety.<
You can inquire about the correct wheel/tire
combination at your BMW Center.
The correct combination of wheels and tires is
also necessary to ensure reliable operation of
various vehicle systems such as ABS and DSC.
To maintain good handling and vehicle
response, only use tires of a single brand and
tread configuration. After a tire has been dam-
aged, for instance, mount the original wheel and
tire combination again as soon as possible.
Recommended tire brands
Certain makes of tire are recommended by
BMW for each tire size. They are marked with a
clearly visible BMW designation on the sidewall
of the tire.
When properly used, these tires meet the high-
est standards in terms of safety and handling
characteristics.
Run-Flat Tires
When mounting new tires or changing over
from summer to winter tires and vice versa,
mount Run-Flat Tires for your own safety. In the
event of a flat, moreover, no spare wheel is
available. Your BMW Center will be glad to pro-
vide you with more information.
For safety reasons, BMW recommends
that damaged Run-Flat Tires be replaced
rather than repaired.<
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 designation provide
better winter traction than summer tires, they
generally do not achieve the full performance of
winter tires.
Pay attention to speed
Always comply with the speed limit for the
winter tires mounted on your car; failure
to do so could result in tire damage and acci-
dents.<
If the car is capable of speeds higher than that
permitted for the winter tires, a label stating the
maximum permitted speed for the mounted
tires must be displayed in your field of view.
Specialist tire dealers and your BMW Center
can supply these labels.
Storage
Store tires in a cool, dry place, protecting them
against light whenever possible. Protect the
tires from contact with oil, grease and fuel. Do
not exceed the maximum tire inflation pressure
indicated on the sidewall of the tire.
Snow chains*
Only certain fine-link snow chains have been
tested by BMW, classified as safe for use and
recommended. Consult your BMW Center for
more information. Attach snow chains in pairs
and only to the rear wheels.
Observe the manufacturer's instructions when
mounting snow chains. Do not exceed a speed
of 30 mph/50 km/h when using snow chains.
You are not permitted to mount snow chains to
tires of the following sizes:
>255/40 R 17
>255/35 R 18
Do not initialize the Flat Tire Monitor if
snow chains are mounted, otherwise the
instrument might issue an incorrect reading.
When driving with snow chains, you may find it
helpful to activate DTC temporarily, refer to
page50.<

Reference
At a glance
Controls
Driving tips
Mobility
121
Starting assistance, refer to
Dynamic Stability Control
DSC49
Starting difficulties
– jump-starting99
– temperature39
Starting with a flat battery,
refer to Jump-starting99
Status of this Owner's Manual
at time of printing5
Steering wheel10
– adjusting34
– buttons on steering
wheel11
– lock38
Steptronic, refer to Sport
program and Manual
operation41
Storage compartments64
– electrical fault64
– eyeglasses compartment65
– glove compartment64
– opening manually64
Storage nets64
Storage space, refer to
– Cargo bay23
Storage space, refer to
Storage compartments64
Storing seat position, refer to
Seat memory32
Stowage, refer to Storage
compartments64
Summer tires, refer to Wheels
and tires80
Supply reservoir, refer to
Washer fluid reservoir44
Switches, refer to Cockpit10
Switch for passenger
airbags35
Switching cooling function on/
off manually59,62
Symbols4
T
Table of contents3
Tachometer46Tailgate21
– emergency operation22
– opening from inside the
vehicle21
– opening from the outside21
– opening manually22
– remote control19
– roller-blind cover65
Tail lamps, refer to Rear
lamps96
Tail lights, refer to Rear
lamps96
Tank contents
– refer to Capacities110
Tank indicator, refer to Fuel
gauge46
Technical data106
Technical modifications, refer
to For your own safety5
Telephone, refer to the
separate Owner's Manual
Telephone preparation
package67
Temperature
– air conditioning59
– automatic climate control62
– coolant, refer to Coolant
thermometer47
– engine47
Temperature display
– outside temperature46
– outside temperature
warning46
– setting unit of measure48
Tempomat, refer to Cruise
control44
Third brake lamp, refer to
Center high-mount brake
lamp96
Three-point safety belt, refer
to Safety belts33
Tilt alarm sensor25
Tilt function, passenger-side
mirror34
Tire inflation pressure80
– checking80
– loss51
– restoring80
Tire renewal84Tires
– age82,84
– break-in procedures70
– changing84
– coding82
– condition83
– damage84
– DOT quality grades82
– flat
51
– inflation pressure80
– pressure monitoring, refer to
Flat Tire Monitor51
– replacement84
– size80
– storage85
– temperature83
– traction83
– tread83
– tread wear83
– Uniform Tire Quality
Grading82
– wear indicators, refer to
Minimum tread depth83
– wheel and tire
replacement84
– winter tires85
– with emergency features,
refer to Run-Flat Tires84
Tire storage85
Tool kit, refer to Onboard tool
kit93
Torque, refer to Engine
data106
Tow bar101
Towing eyelet100
Towing the vehicle100
– methods101
– with automatic
transmission101
Tow rope101
Tow-starting101
Tow truck101
Track width, refer to
Dimensions107,108
Traction control, refer to
Dynamic Stability Control
DSC49