2004 BMW 645CI COUPE&CONVERTIBLE wheel size

Wheels and tires
164
Wheels and tires
Tire inflation pressure
Information for your safety
It is not merely the tire's service life, but
also driving comfort and – to a great extent
– driving safety that depend on the condi-
tion of the tires and the maintenance of the
specified tire pressure.
Check the tire inflation pressure regu-
larly and correct it if necessary: at
least every two weeks and before begin-
ning a longer trip. If you fail to observe this
precaution, you may be driving on tires with
incorrect tire pressures, a condition that
can not only compromise your vehicle's
stability, but also lead to tire damage and
the risk of an accident.<
Checking tire inflation pressure
Only check tire inflation pressure 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. When tires are warm, the tire infla-
tion pressure increases.
After correcting the inflation pres-
sure(s), always reinitialize the Flat Tire
Monitor, refer to page 79.<
Inflation pressures for original tires
The tires must be at ambient temperature.
The inflation pressures, provided on a label
affixed to the B-pillar, are visible when the
driver's door is open.
Inflation pressure for other tire sizes
The tables below provide all the correct
inflation pressures for the specified tire
sizes at ambient temperature.
For correct identification of the right
tire inflation pressure for your tires,
observe the specifications for the corre-
sponding tire size.<
Observe tire size
The specified pressures apply to tire sizes
approved by BMW and recommended tire
makes; your BMW center will be glad to
provide information.

Wheels and tires
166
Tire identification marks
Knowledge of the labeling on the side of
the tire makes it easier to identify and
choose the right tires.
Tire size
Speed letter
T = up to 118 mph/190 km/h
H = up to 131 mph/210 km/h
V = up to 150 mph/240 km/h
W = up to 167 mph/270 km/h
Y = up to 186 mph/300 km/h
Tire Identification Number
Tires with DOT codes meet the guidelines
of the U.S. Department of Transport.
DOT code:
Tire age
The tire's date of manufacture is indicated
on the sidewall:
DOT ... 1204 indicates that a tire was man-
ufactured in week 12 of the year 2004.
BMW recommends for various reasons,
including beginning brittleness, replacing
all tires after 6 years at the latest, even if a
tire age of 10 years is possible.
Uniform Tire Quality Grading
Quality grades can be found where appli-
cable on the tire sidewall between tread
shoulder and maximum section width.
For example:
Treadwear 200 Traction AA
Temperature A
DOT Quality Grades
Treadwear
Traction AA A B C
Temperature A B C
All passenger car tires must conform
to Federal Safety Requirements in
addition to these grades.<
Treadwear
The treadwear grade is a comparative rat-
ing based on the wear rate of the tire when
tested under controlled conditions on a
specified government test course.
For example, a tire graded 150 would wear
one and one-half, 1g, times as well on the
government course as a tire graded 100.
The relative performance of tires depends
upon the actual conditions of their use,
however, and may depart significantly from
the norm due to variations in driving habits,
service practices and differences in road
characteristics and climate.
Traction
The 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 specified govern-
ment 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 brak-
ing traction tests, and does not include
acceleration, cornering, hydroplaning, or
peak traction characteristics.< e.g.
Nominal width
in mm
Aspect ratio in X
Radial type
Rim diameter in inches
Load rating
not on ZR tires
Speed rating
before R on ZR tires
205/60 R1591W
e.g.
Manufacturer code
for tire make
Tire size and tire design
Tire ageDOT xxxx xxx 1204

Wheels and tires
168
Run-flat tires
You will recognize run-flat tires by a circular
symbol containing the letters RSC on the
side of the tire.
Run-flat tires consist of self-contained tires
and special rims. The tire reinforcement
ensures that the tire retains some residual
safety in the event of pressure drop and
driving remains possible to a restricted
degree.
Continuing driving with a damaged
tire
Driving on run-flat tires with tire damage
can continue, depending on the vehicle
load and the severity of the tire damage, at
a maximum speed of 50 mph/80 km/h.
You can estimate the possible mileage for
continued driving on the basis of the fol-
lowing general indications:
>With low load:
1 to 2 persons without luggage:
Approx. 155 miles/250 km
>With medium load:
2 persons, luggage compartment full, or
4 persons without luggage:
Approx. 94 miles/150 km
>With full load:
4 persons, luggage compartment full:
Approx. 30 miles/50 km.
Drive reservedly and do not exceed
a speed of 50 mph/80 km/h. In the
event of pressure loss, vehicle handling
changes. This includes reduced track sta-
bility in braking, extended braking distance
and altered natural steering characteristics.
If unusual vibrations occur while the vehicle
is being driven, this can indicate final failure of the damaged tire. Reduce speed and
stop as soon as possible. Do not continue
driving. Contact your BMW center.<
New wheels and tires
You can find out the right wheel-tire combi-
nation from your BMW center. It is another
vital factor in ensuring reliable operation of
various vehicle systems such as ABS and
DSC. Have the wheel and tire assemblies
balanced every time either a wheel or a tire
is replaced.
Only have new wheels and tires
mounted by a specialist. If this work is
performed inexpertly, there is a danger of
damage and associated safety risks.<
Retreaded tires
BMW does not recommend the use of
retread tires, as otherwise driving
safety may be reduced. Possible variations
in the design and the age – which could be
substantial – of the carcasses can lead to
unusually rapid wear.<
The right wheels and tires
BMW recommends that you use only
wheel and tire combinations that
BMW has tested and approved for your
particular vehicle. Variations in factors such
as manufacturing tolerances mean that
even wheels and tires with identical official
size ratings could actually have different
dimensions than the approved units – these
differences could lead to body contact, and
with it the risk of severe accidents. If non-
approved wheels and tires are used, BMW
cannot evaluate their suitability, and there-
fore cannot be held liable for driving
safety.<
To maintain good handling and vehicle
response, use only tires of a single tread
configuration from a single manufacturer.
After a flat tire, always remember to have
the specified wheel and tire combination
remounted on the vehicle as soon as pos-
sible.

Mobility
169Reference
At a glance
Controls
Driving tips
Communications
Navigation
Entertainment
Recommended tire sizes and makes
BMW tests certain tire brands for each tire
size, classifies them as road-safe and
approves them. You can find out about
these at specialized dealers or at your
BMW center. Observe any country-specific
regulations, e.g. on making a correspond-
ing entry in the vehicle documents.
The factory-mounted tires have been spe-
cially selected to provide optimized perfor-
mance when installed on your vehicle; if
properly cared for, they will provide a com-
bination of safety and excellent ride com-
fort.
Run-flat tires
In the event of replacement, use run-flat
tires, refer to page 168, as there is no spare
wheel available for flats.
For safety reasons, BMW recom-
mends that you do not have damaged
run-flat tires repaired; they should be
replaced.<
Special characteristics of winter
tires
BMW recommends winter tires for use in
cold winter driving conditions. Although all-
season M+S tires provide better winter
traction than summer tires, they generally
fail to provide the same levels of cold-
weather performance as winter tires.
Run-flat tires
If you switch from summer to winter tires,
or vice versa, use run-flat tires, refer to
page 168, as in the event of a flat tire there
is no spare tire available. Your BMW center
will be glad to advise you.
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 technicians at your
BMW center will be glad to assist you with the required professional knowledge and
specialized equipment.<
Storage
Always store wheels and tires in a cool, dry
place with as little exposure to light as pos-
sible. Always protect tires against all con-
tact with oil, grease and fuels. Do not
exceed the maximum tire inflation pressure
indicated on the side wall of the tire.
Snow chains*
BMW only tests certain snow chains, clas-
sifies them as road-safe and approves
them. Consult your BMW center for more
information. BMW recommends using
these approved, narrow-link snow chains.
These snow chains are approved exclu-
sively for use in pairs on the rear wheels
with the tire size 245/45 R 18.
Observe the manufacturer's instructions
when mounting snow chains.
Do not exceed a vehicle speed of 30 mph/
50 km/h with the chains mounted.
Do not initialize the Runflat Indicator
after mounting snow chains.
When you are driving with snow chains, it
can be beneficial to switch off DSC briefly,
refer to page 77.<

Reference 209
At a glance
Controls
Driving tips
Communications
Navigation
Entertainment
Mobility
Starting difficulties
– jump-starting 184
– refer to Starting engine 54
Starting engine 54
Start menu 17
"Start route guidance" 112
"Start service" 157
"State / Province" for desti-
nation entry 110
"State inspection" 66
Station, refer to Radio 130
"Status" 65
Status of this Owner's
Manual at time of
printing 5
Steering wheel 11
– adjustment 48
– automatic adjustment 49
– buttons on steering
wheel 11
– heating 49
– individual button
assignment options 49
– memory 44
"Steering wheel
buttons" 49
Steering with variable ratio,
refer to Active steering 80
Steptronic, refer to
Automatic transmission
with Steptronic 58
"Stop" for stopwatch 72
"Stopwatch" 72
Stopwatch 72
Storage compartments 96
"Store in address book" for
navigation 114
"Store" on the
radio 132, 135
Storing current
position 114
Storing sitting position,
refer to Seat, mirror and
steering wheel
memory 44
Storing tires 169
Straps, refer to
Loading 105
"Street" for destination
entry 111Stroke, refer to
Engine data 190
Summer tires, refer to
Wheels and tires 164
SW, waveband 130
Switches, refer to
Cockpit 10
Switching navigation voice
instructions on/off 119
Switching off
– engine 55
– interior motion sensor 33
– tilt alarm sensor 33
Switching on
– audio 126
– CD changer 126
– CD player 126
– portable phone 145
– radio 126
Switching on hour signal 73
Switching the cooling
function on and off 89
Swiveling headlamps, refer
to Adaptive Head Light 86
Symbols 4
T
Tachometer 64
Tail lamps 180
– replacing the bulbs 180
Tank capacity, refer to
Fuel tank capacity 162
Target cursor for
navigation 112
Technical changes, refer to
For your own safety 6
Technical data 190
Telematic 155
Telephone
– refer to Portable
phone 144
– refer to separate
Owner's Manual
TeleService 155
– enabling 155
– services offered 156
Temperature
adjustment 89Temperature display
– ice warning 64
– outside temperature 64
– setting measurement
units 64
Temperature gauge,
engine oil 65
Tempomat, refer to
Cruise control 62
"Terminate services" 158
"Text language" 73
The individual vehicle 5
Tilt function, passenger-
side mirror 45
"Time" 73
"Time 1" for independent
ventilation 93
"Time 2" for independent
ventilation 93
"Time format" 73
Timer, refer to Preselecting
activation time 93
Tire pressure monitoring,
refer to Flat Tire
Monitor 79
Tire Quality Grading 166
Tires
– age 166
– air loss 80
– break-in procedure 102
– changing 168
– condition 167
– damage 167
– flat 168
– inflation pressure 164
– new wheels and tires 168
– pressure monitoring, refer
to Flat Tire Monitor 79
– replacing 168
– retreaded tires 168
– run-flat tires 168
– size 168
– tread 167
– wear indicators 167
– wheel/tire
combination 168
– winter tires 169
"Tone" 128
Tone in audio mode
– adjusting 127
– middle setting 129