2008 BMW 128I CONVERTIBLE Owner's Manual

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Convertible: tire inflation pressures for the 135i
Tire size Pressure specifications in psi/kPa
Traveling speeds
up to a max. of
100 mph / 160 km/hTraveling speeds
including those exceeding
100mph / 160km/h
All pressure specifications in
the table are indicated in
psi/kilopascal with cold tires.
Cold = ambient temperature
205/50 R 17 89 H M+S 33/220 38/260 32/220 35/240 36/250 42/290
Front: 215/40 R 18 85 Y 39/270 - 39/270 - 39/270 -
Rear: 245/35 R 18 88 Y - 39/270 - 39/270 - 39/270
with Sports package
205/50 R 17 89 H M+S 33/220 38/260 33/230 36/250 38/260 45/310
Front: 215/40 R 18 85 Y 39/270 - 38/260 - 39/270 -
Rear: 245/35 R 18 88 Y - 39/270 - 38/260 - 45/310
More details on the permissible load and weights can be found on page239.

Wheels and tires
208
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 code letter
Q = up to 100 mph or 160 km/h
T = up to 118 mph or 190 km/h
H = up to 131 mph or 210 km/h
V = up to 150 mph or 240 km/h
W = up to 167 mph or 270 km/h
Y = up to 186 mph or 300 km/h
Tire Identification Number
Tires with DOT codes meet the guidelines of
the US Department of Transportation.
DOT code:
Tire age
The manufacturing date of tires is contained in
the tire coding: DOT … 0708 means that the
tire was manufactured in week 7 of 2008.
BMW recommends that you replace all tires
after 6 years at most, even if some tires may last
for 10 years.
Uniform Tire Quality Grading
Quality grades can be found where applicable
on the tire sidewall between tread shoulder and
maximum section width. For example:
Tread wear 200 Traction AA
Temperature A
DOT Quality Grades
Tread wear
Traction AA A B C
Temperature A B C
All passenger car tires must conform to
Federal Safety Requirements in addition
to these grades.<
Tread wear
The tread wear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified gov-
ernment test course. For example, a tire graded
150 would wear one and one-half (1γ) 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, how-
ever, and may depart significantly from the
norm due to variations in driving habits, service
practices and differences in road characteris-
tics 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 government test sur-
faces 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 braking traction
tests, and does not include acceleration, cor-
nering, hydroplaning, or peak traction charac-
teristics.<
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 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 tires
225/45 R1791 V
e.g.
Manufacturer's
code for tire make
Tire size and
tire design
Tire ageDOT xxxx xxx 0708

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heat when tested under controlled conditions
on a specified indoor laboratory 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 Vehi-
cle Safety Standard No. 109. Grades B and A
represent 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,
underinflation, or excessive loading, either sep-
arately or in combination, can cause heat
buildup and possible tire failure.<
RSC – Run-Flat Tires
You will recognize Run-Flat Tires by a circular
symbol containing the letters RSC on the side
of the tire, refer to page210.
M+S
Winter and all-season tires.
These have better winter properties than sum-
mer tires.
XL
Designation for specially reinforced 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.
Minimum tread depth
The tire tread depth should not be below 1/8 in/
3 mm. At tread depths below 1/8 in/3 mm there
i s a n i n c r e a s e d r i s k o f h i g h - s p e e d h y d r o p l a n i n g ,
even when only small amounts of water are
present on the road surface.
The tread depth should not drop below 1/8 in/
3 mm, although, for example, European legisla-
tion only specifies a minimum tread depth of 1/16 in/1.6 mm. At tread depths below 1/8 in/
3 mm there is an increased risk of high-speed
hydroplaning, even when only small amounts of
water are present on the road surface.
When winter tires wear down past a tread depth
of 1/6 in/4 mm, they become perceptibly less
suitable for winter conditions. In the interest of
safety, new tires should be installed.
Wear indicators in the base of the tread groove
are distributed around the tire's circumference;
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
Please note that low-profile tires cause wheels,
tires and suspension parts to be more suscep-
tible to road hazard and consequential dam-
ages.
Unusual vibrations encountered during normal
vehicle operation can indicate tire failure or
some other vehicle defect. This can, for exam-
ple, 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.
Otherwise, tire damage can pose a lethal hazard
to vehicle occupants and other road users.<

Wheels and tires
210
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 manufacturing date of tires is contained in
the tire coding:
DOT ... 0708 means that the tire was manufac-
tured in week 7 of 2008.
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 Indication of a flat tire on page85.
New wheels and tires
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. If this
work is not carried out properly, there is a dan-
ger of subsequent damage and related safety
h a z a r d s . M a k e s u re t h a t t h e n e w w h ee l s a r e b a l-
anced.<
Retreaded tires
BMW recommends that you do not use
retreaded tires, since driving safety may be impaired. The causes for this include poten-
tially different tire casing structures and often
wide variations in tire age, which can result in a
limited service life.<
Correct wheels and 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, no spare wheel is available. Your
BMW center will be glad to advise you.
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 manufac-
turing tolerances mean that even wheels and
tires with identical official size ratings could
actually have different dimensions, which could
lead to body contact and thus to severe acci-
dents. If non-approved wheels and tires are
used, BMW cannot evaluate their suitability,
and therefore cannot guarantee their driving
safety.<
You can inquire about the right wheel/tire com-
bination 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, DSC or
FTM.
To maintain good handling and vehicle
response, use only tires of a single brand and
tread configuration. After a tire has been dam-
aged, mount the previous wheel and tire combi-
nation again as soon as possible.
Wheels with Tire Pressure Monitor
TPM electronics
When mounting new tires or changing over
from summer to winter tires, or vice versa, only
use wheels with TPM electronics; otherwise the
Tire Pressure Monitor may not be able to detect
a puncture, refer to page87. Your BMW center
will be glad to advise you.

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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.
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.
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 wheels and tires in a cool, dry place with
as little exposure to light as possible. Always
protect tires against all contact with oil, grease
and fuels.
Do not exceed the maximum tire inflation pres-
sure indicated on the sidewall of the tire.
Swapping wheels between axles
BMW advises against swapping wheels
between the front and rear axles, even if all tires
have the same size, as this could impair driving
characteristics. If the tires are of mixed sizes,
swapping wheels between the axles is not per-
missible.
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. Snow chains must be
mounted in pairs and on the rear wheels only.
Observe the manufacturer's instructions when
mounting snow chains. Do not exceed a speed
of 30 mph/50 km/h with chains.
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
page82.<

Under the hood
212
Under the hood
Do not work on the car unless you pos-
sess the necessary technical knowledge.
If you are unfamiliar with the statutory guide-
lines, have any work on the vehicle performed
only by a BMW center or by a workshop that
work according to BMW repair procedures with
correspondingly trained personnel. If this work
is not carried out properly, there is a danger of
subsequent damage and related safety haz-
ards.<
Hood
Releasing
Pull the lever.
Opening
To avoid damage, make sure that the
wiper arms are against the windshield
before you open the engine compartment. Do
not open the engine hood before the engine has
cooled down, otherwise injuries may result.<
Press the release handle and open the hood.
Closing
Close the hood from a height of approx. 16 in/
40 cm with momentum. It must be clearly heard
to engage.
Make sure that the closing path of the
hood is clear, otherwise injuries may
result.
If you see any signs while driving your vehicle
that the hood is not completely closed, stop at
once and close it securely.<

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Important parts of the engine compartment
1Expansion tank for coolant, refer to
page216
2Washer fluid filler neck for headlamp clean-
ing system and window washer system,
refer to page643Jump-starting connection, refer to
page230
4Fluid filler neck for engine oil, refer to Add-
ing engine oil, page215
Engine oil
The engine oil consumption is dependent on
driving style and driving conditions.
Checking oil level
Your car is equipped with an electronic oil-level
monitor.
For a precise measurement and display of the
oil level, it is necessary that the engine be at
operating temperature, i.e. after uninterrupted
driving for at least approx. 6.5 miles/10 km. You
can have the oil level displayed while you are
driving, or while the vehicle is at a standstill on a
level surface and the engine is running.
Display in the instrument cluster
1.Push button 1 in the turn indicator lever up
or down repeatedly until the appropriate
symbol is shown in the display, accompa-
nied by the word "OIL".
2.Press button 2.
The oil level is checked and the reading dis-
played.

Under the hood
214
Possible displays
1Oil level OK
2Oil level is being checked.
This can take about 3 minutes if the car is at
a standstill on a level surface, or about
5 minutes while the car is on the move.
3Oil level down to minimum:
Add engine oil as soon as possible, but no
more than 1 US quart/1 liter, refer also to
Adding engine oil on page215.
4Oil level is too high.
Too much oil will harm the engine.
Have the vehicle checked without
delay.<
5The oil level sensor is defective.
Do not add engine oil. You can continue
your journey. Note the newly calculated dis-
tance remaining to the next oil service, refer
to page217. Have the system checked as
soon as possible.
Display via iDrive
iDrive, for operating principle refer to page16.1.Press the button.
This opens the start menu.
2.Press the controller to open the menu.
3.Select "Info sources" and press the control-
ler.
4.Select "Service" and press the controller.
5.If necessary, move the highlight marker to
the uppermost field. Turn the controller
until "Service requirements" is selected and
press the controller.
6.If necessary, move the highlight marker to
the second field from the top. Turn the con-
troller until "Engine oil level" is selected and
press the controller.
The oil level is displayed.
To exit the display immediately:
Select and press the controller.