2010 BMW Z4 ROADSTER SDRIVE30I tires

Things to remember when driving
114 The risk of hydroplaning increases with declin-
ing tread depth on the tires, refer also to Mini-
mum tread depth on page198.
Driving through water
Drive though calm water only if it is not
deeper than 1 ft/25 cm and at this height
no faster than walking speed, up to 6 mph/
10 km/h. Otherwise, the vehicle's engine, the
electrical systems and the transmission may be
damaged.<
Use the parking brake on inclines
On inclines, do not hold the vehicle for a
lengthy period using the clutch; use the
parking brake instead. Otherwise, greater
clutch wear will result.<
For more information about the drive-off assis-
tant, refer to page80.
Braking safely
Your BMW is equipped with ABS as a standard
feature. Applying the brakes fully is the most
effective way of braking in situations in which
this is necessary. Since the vehicle maintains
steering responsiveness, you can still avoid
possible obstacles with a minimum of steering
effort.
Pulsation of the brake pedal, combined with
sounds from the hydraulic circuits, indicate that
ABS is in its active mode.
Driving in wet conditions
When roads are wet or there is heavy rain,
briefly exert gentle pressure on the brake pedal
every few miles. Monitor traffic conditions to
ensure that this maneuver does not endanger
other road users. The heat generated in this
process helps dry the pads and rotors. Full
braking efficiency will then be available when
you need it.
Hills
To prevent overheating and the resulting
reduced efficiency of the brake system,
drive long or steep downhill gradients in the
gear in which the least braking is required. Even light but consistent brake pressure can lead to
high temperatures, brake wear and possibly
even brake failure.<
You can increase the engine's braking effect by
shifting down, all the way to first gear if neces-
sary. This strategy helps you avoid placing
excessive loads on the brake system. Down-
shifting in manual mode of the automatic trans-
mission, refer to page54.
7-gear sport automatic transmission with
dual clutch: Never drive with the trans-
mission in neutral or with the engine switched
off; otherwise, engine braking action will not be
present or there will be no power assistance to
the brakes or steering.
Manual transmission: Never drive with the
clutch held down, with the transmission in neu-
tral or with the engine switched off; otherwise,
engine braking action will not be present or
there will be no power assistance to the brakes
or steering.
Never allow floor mats, carpets or any other
objects to protrude into the area around the
pedals; otherwise, pedal function could be
impaired.<
Corrosion on brake rotors
When the vehicle is driven only occasionally,
during extended periods when the vehicle is not
used at all, and in operating conditions where
brake applications are less frequent, there is an
increased tendency for corrosion to form on
rotors, while contaminants accumulate on the
brake pads. This occurs because the minimum
pressure which must be exerted by the pads
during brake applications to clean the rotors is
not reached.
Should corrosion form on the brake rotors, the
brakes will tend to respond with a pulsating
effect that even extended application will fail
to cure.
When the vehicle is parked
Condensation forms while the automatic cli-
mate control is in operation, and then exits
under the vehicle. Traces of condensed water
under the vehicle are therefore normal.

Driving tips
115Reference
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Mobility
Before driving into a car wash
General information on caring for your BMW
can be found on page208.
With Comfort Access and automatic
transmission
Insert the remote control into the ignition
switch.
The engine can be switched off when the selec-
tor lever is in position N. Refer also to page208.
With Comfort Access and 7-gear sport
automatic transmission with dual
clutch
Insert the remote control into the ignition
switch.
The engine can be switched off when the trans-
mission is in position N. Refer also to page209.
Cargo loading
To avoid loading the tires beyond their
approved carrying capacity, never over-
load the vehicle. Overloading can lead to over-
heating and increases the rate at which damage
develops inside the tires. This can ultimately
result in a sudden blowout.<
Make sure that no liquids are spilled or
leak from their containers in the cargo
area, as this could result in damage to the
vehicle.<
Always position and secure the cargo as
described so that it cannot endanger the
car's occupants, for example if sudden braking
or swerving is necessary.
Never exceed either the approved gross vehicle
weight or either of the approved axle loads, refer
to page228, as excessive loads can pose a
safety hazard, and may also place you in viola-
tion of traffic safety laws.
Heavy or hard objects should not be carried
loose inside the car, since they could be thrown
around, for example as a result of heavy braking,
sudden swerves, etc., and endanger the occu-
pants.<
Determining loading limit
1.Locate the following statement on your
vehicle's placard
*:
The combined weight of occupants
and cargo should never exceed
XXX kg or YYY lbs. Otherwise, overloading
can result in damage to the vehicle and
unstable driving conditions.<
2.Determine the combined weight of the
driver and passengers that will be riding in
your vehicle.
3.Subtract the combined weight of the driver
and passengers from XXX kilograms or YYY
pounds.
4.The resulting figure equals the available
amount of cargo and luggage load capacity.
For example, if the YYY amount equals
1,400 lbs and there will be five 150 lbs
passengers in your vehicle, the amount of
available cargo and luggage load capacity
is 650 lbs:
1,400 lbs minus 750 lbs = 650 lbs
5.Determine the combined weight of luggage
and cargo being loaded on the vehicle. That
weight may not safely exceed the available
cargo and luggage load capacity calculated
in step 4.
6.If your vehicle will be towing a trailer, part of
the load from your trailer will be transferred
to your vehicle. Consult the manual for
transporting a trailer to determine how this
may reduce the available cargo and luggage
load capacity of your vehicle.

Mobility
This section helps you maintain your car's
mobility by supplying important information
on vital topics including fuels and lubricants,
wheels and tires, service, maintenance and
breakdown assistance.
Mobility

Wheels and tires
194
Wheels and tires
Tire inflation pressures
Information for your safety
It is not merely the tires' service life, but also
driving comfort and, to a great extent, driving
safety that depend on the condition of the tires
and the maintenance of the specified tire
pressure.
Check the tire inflation pressure regularly
and correct it, if necessary: at least twice a
month and before starting long trips. If you fail
to observe this precaution you may be driving
on tires with incorrect tire pressures, a condi-
tion that can not only compromise your vehi-
cle's driving stability, but also lead to tire dam-
age 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 seriously 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
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 inflation pressure is higher.
After correcting the tire inflation pressure,
reinitialize the Tire Pressure Monitor,
refer to page83, or the Flat Tire Monitor, refer
to page81.<
Inflation pressure specifications
The tables below provide all the correct inflation
pressures for the specified tire sizes at ambient
temperature.
The inflation pressures apply to the tire
sizes approved and tire brands recom-
mended by BMW; a list of these is available
from your BMW center.<
For correct identification of the right tire infla-
tion pressures, observe the following:>Tire sizes for your vehicle
>Load conditions
>Maximum allowable driving speed
Tire inflation pressures for driving up to
100 mph or 160 km/h
For normal driving up to 100 mph or 160 km/h
and to achieve optimum driving comfort, adjust
pressures to the respective tire inflation pres-
sures listed on the following pages in the col-
umns for traveling speeds up to a maximum of
100 mph or 160 km/h.
These tire inflation pressures can also be found
on the driver's side door post when the driver's
door is open.
The maximum permissible speed for
these tire pressures is 100 mph or
160 km/h. Do not exceed this speed; otherwise,
tire damage and accidents could occur.<
Tire inflation pressures for driving
above 100 mph or 160 km/h
In order to drive at maximum speeds in
excess of 100 mph or 160 km/h, adjust
pressures to the respective tire inflation pres-
sures listed on the following pages in the col-
umns for traveling speeds including those
exceeding 100 mph or 160 km/h. Otherwise,
tire damage and accidents could occur.<
Observe all national and local maximum speed
limits; otherwise, violations of the laws could
occur.

Mobility
195Reference
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Tire inflation pressures Z4 sDrive30i
Tire size Pressure specifications in psi/kPa
Traveling speeds
up to a max. of
100 mph/160 km/hTraveling speeds
including those exceeding
100 mph/160 km/h
All pressure specifications in
the table are indicated in
psi/kilopascal with cold tires.
Cold = ambient temperature
without Sport Package:
225/45 R 17 91 V
225/45 R 17 91 H M+S
225/45 R 17 94 V M+S XL36/250 44/300 36/250 44/300
Front: 225/45 R 17 91 V 36/250 - 36/250 -
Rear: 255/40 R 17 94 V - 39/270 - 39/270
Front: 225/40 R 18 88 W 36/250 - 36/250 -
Rear: 255/35 R 18 90 W - 42/290 - 42/290
Front: 225/35 R 19 88 Y XL 36/250 - 36/250 -
Rear: 255/30 R 19 91 Y XL - 42/290 - 42/290
with Sport Package:
225/45 R 17 91 W
225/45 R 17 91 H M+S
225/45 R 17 94 V M+S XL36/250 44/300 36/250 44/300
Front: 225/45 R 17 91 W 36/250 - 36/250 -
Rear: 255/40 R 17 94 W - 39/270 - 39/270
Front: 225/40 R 18 88 W 36/250 - 38/260 -
Rear: 255/35 R 18 90 W - 42/290 - 45/310
Front: 225/35 R 19 88 Y XL 36/250 - 36/250 -
Rear: 255/30 R 19 91 Y XL - 42/290 - 44/300
More details on the permissible load and weights can be found on page228.

Wheels and tires
196
Tire inflation pressures Z4 sDrive35i
Tire size Pressure specifications in psi/kPa
Traveling speeds
up to a max. of
100 mph/160 km/hTraveling speeds
including those exceeding
100 mph/160 km/h
All pressure specifications in
the table are indicated in
psi/kilopascal with cold tires.
Cold = ambient temperature
without Sport Package:
225/45 R 17 91 H M+S
225/45 R 17 94 V M+S XL36/250 44/300 36/250 44/300
Front: 225/45 R 17 91 V 36/250 - 36/250 -
Rear: 255/40 R 17 94 V - 39/270 - 39/270
Front: 225/40 R 18 88 W 36/250 - 36/250 -
Rear: 255/35 R 18 90 W - 42/290 - 42/290
Front: 225/35 R 19 88 Y XL 36/250 - 36/250 -
Rear: 255/30 R 19 91 Y XL - 42/290 - 42/290
with Sport Package:
225/45 R 17 91 H M+S
225/45 R 17 94 V M+S XL36/250 44/300 36/250 44/300
Front: 225/45 R 17 91W 36/250 - 36/250 -
Rear: 255/40 R 17 94 W - 39/270 - 39/270
Front: 225/40 R 18 88 W 36/250 - 38/260 -
Rear: 255/35 R 18 90 W - 42/290 - 45/310
Front: 225/35 R 19 88 Y XL 36/250 - 36/250 -
Rear: 255/30 R 19 91 Y XL - 42/290 - 44/300
More details on the permissible load and weights can be found on page228.

Mobility
197Reference
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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 … 3709 means that the
tire was manufactured in week 37 of 2009.
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.< For example:
Nominal width in mm
Aspect ratio in %
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
For example:
Manufacturer's code
for tire make
Tire size and
tire design
Tire ageDOT xxxx xxx 3709

Wheels and tires
198
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 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 page199.
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 tread depth should not drop below 1/8 in/
3mm, 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 sus-
ceptible to road hazard and consequential
damages.
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 be extremely dan-
gerous for vehicle occupants and other road
users.<