2009 PORSCHE 911 wheel size

Operation, Safety
45
fUsing accessories not approved by Porsche
can cause the weight sensing system to be im-
paired.
fDo not squeeze objects, such as the fire extin-
guisher, or first aid kit under the seat.
fOnly have seats removed and installed by an
authorized Porsche dealer so that weight sens-
ing components will not be damaged.
fGive your passenger all of the information in
this chapter.
Note
Airbag components (e.g. steering wheel, door lin-
ing, seats) may be disassembled only by an autho-
rized Porsche dealer.
When disposing of a used airbag unit, our safety
instructions must be followed. These instructions
can be obtained at any authorized Porsche dealer.
Function of the airbag systemAirbags are a supplemental safety system. Your
primary protection comes from your safety belts.
The front airbags are triggered during a frontal col-
lision of sufficient force and direction.
In the event of a side impact of corresponding
force, the side airbag on the impact side is
triggered.
The inflation process generates the amount of gas
required to fill the airbags at the necessary pres-
sure in fractions of a second.Airbags help to protect the head and upper body,
while simultaneously damping the motion of the
driver and passenger in the impact direction in the
event of a frontal impact or side impact.
In order to help provide protection in severe colli-
sions which can cause death and serious injury,
airbags must inflate extremely rapidly. Such high
speed inflation has a negative but unavoidable
side effect, which is that it can and does cause in-
juries, including facial and arm abrasions, bruising
and broken bones. You can help minimize such in-
juries by always wearing your safety belts.
There are many types of accidents in which
airbags are not expected to deploy. These include
accidents where the airbags whould provide no
benefit, such as a rear impact against your vehi-
cle. Other accidents where the airbags are de-
signed not to deploy are those where the risk of
injury from the airbag deployment could exeed any
protective benefits, such as in low speed acci-
dents or higher speed accidents where the vehicle
decelerates over a longer time. Since airbag de-
ployment does not occur in all accidents, this fur-
ther emphasizes the need for you and your pas-
sengers to always wear safety belts.
Your vehicle is equipped with a crash sensing and
diagnostic module. This module will record the
use of the seat belt restraint system by the driver
and front passenger when the airbags and/or belt
tensioner work.
Advanced AirbagYour vehicle is equipped with a weight sensing sys-
tem for the passenger's seat in accordance with
U.S. Federal Motor Vehicle Safety Standard 208.
Depending on the weight acting on the front pas-
senger's seat, the front passenger's airbag will au-
tomatically be switched on and off.
Depending on the angle and force of impact, the
front passenger's airbag which is activated will be
triggered during a collision.
Precondition for switching the front passenger's
airbag on and off, depending on weight:
– Vehicles equipped with key-operated airbag
deactivation device:
Switch position AUTO.
– Ignition key is inserted.
Improper handling of the weight sensing
system can unintentionally impair switching
the passenger's airbag off and on.

Operation, Safety
63
Porsche Traction Management
(PTM)With PTM, the engine power is variably distributed
to the front and rear wheels.
Power distribution between the front and rear ax-
les is performed by a map-conrolled multiple-disc
clutch.
Distribution of the engine power also depends on
the difference in wheel speed between the two ax-
les.
The multiple-disc clutch always delivers sufficient
drive power to the front wheels to ensure optimum
propulsion even on an unfavorable road surface.
In combination with the Porsche Stability Manage-
ment (PSM), the PTM ensures optimum handling
and high driving stability.
Warning!
The increased control that is provided should
not induce you to take greater risks with your
safety. The limits dictated by the laws of phy-
sics cannot be overcome, even with PTM.
The risk of accidents due to inappropriate
speed cannot be reduced, even by PTM.
The driver bears the responsibility for all dri-
ving maneuvers.
fAdapt your driving style to the prevailing road
and weather conditions.
fObey all traffic laws.
Dynamometer testing procedure Some U.S. states and Canadian provinces con-
duct emissions inspection/maintenance testing in-
volving the use of two-wheel dynamometer.
A two-wheeled dynamometer is a treadmill type
device upon which a single axle of the car, the dri-
ving axle of the vehicle, rotates to simulate vehicle
operation on the road while the vehicle remains
stationary.
Your vehicle has a full-time four-wheel drive system
which cannot be disabled. Severe damage to the
powertrain can result if tested on a two-wheel dy-
namometer.
Warning!
Risk of severe powertrain damage and a pos-
sible unexpected movement of the vehicle.
fDo not test your vehicle on a two-wheel dyna-
mometer.
fAdvise the emission station of this warning be-fore testing the vehicle.
Brake testsBrake tests must be performed only on plate-type
test stands or roller test stands.
The ignition must be off.
The following limit values must not be exceeded
on roller test stands:
– Testing speed 5 mph (8 km/h)
– Test duration 20 seconds Handbrake tests Handbrake tests on the roller test stand must only
be carried out with the ignition switched off. Balancing wheels on the vehicle During finish balancing of the wheels, the vehicle
must be hoisted and all the wheels able to rotate
freely. Towing fPlease see the chapter “TOWING” on
Page 280.Wheels/TiresThe PTM control unit is adapted to the approved
tire sizes. The use of non-approved tire sizes may
lead to deviations in wheel speeds and it may influ-
ence handling or result in the PTM switching off.

Instruments, On-Board Computer, Warnings
143
TPM
Tire Pressure MonitoringfPlease see the chapter “TIRE PRESSURES FOR
COLD TIRES (68 °F / 20 °C)” on Page 289.
The Tire Pressure Monitoring continuously
monitors tire pressure and tire temperature on all
four wheels and warns the driver when the tire
pressure is too low.
The display as well as the settings for the Tire
Pressure Monitoring take place on the on-board
computer.
However, you must still adjust the tire pressure on
the wheel.fThe driver is responsible for filling the tires
correctly and making the correct settings on
the on-board computer.
The Tire Pressure Monitoring offers the following
functions:
– Display of the actual tire pressure while the
vehicle is in motion.
– Display of the deviation from the required
pressure (refilling pressure).
– Display of currently set tire size and type.
– Tire pressure warnings in two stages.
Warning!
fDespite the advantages offered by the Tire
Pressure Monitoring, it is still the driver’s re-
sponsibility to update the corresponding set-
tings in the on-board computer and maintain
the pressure in the tires.
Low tire pressure reduces the road safety of
the vehicle and destroys the tire and wheel.
fWhen a flat tire has been displayed, immedi-
ately stop in a suitable place and check the
tires for damage. If necessary, remedy the
damage with a tire sealant.
fDo not by any means continue to drive with
damaged tires.
fSealing the tire with tire sealant is only an
emergency repair, so you can drive to the next
authorized Porsche dealer. The maximum per-
mitted speed is 50 mph (80 km/h).fDo not drive with tires whose tire pressure
drops again in a short period of time. In cases
of doubt, have tires checked by an authorized
Porsche dealer.
fDamaged tires must be immediately replaced
by an authorized Porsche dealer.
Tire repairs are not permissible under any
circumstances.
fIf a fault occurs in the Tire Pressure Monitoring
(e.g. defective wheel transmitter), contact an
authorized Porsche dealer immediately and
have the damage repaired.
The tire pressure will not be monitored at all or
will be monitored only partially by defective
Tire Pressure Monitoring.
fTires lose air over time without a tire defect
being present. A tire pressure warning will then
appear in the on-board computer display.
Correct the tire pressure at the next oppor-
tunity.
fThe Tire Pressure Monitoring gives a warning
about tire damage due to natural pressure loss
as well as about a gradual loss of pressure due
to foreign objects.
The Tire Pressure Mnitoring cannot warn you
about tire damage that occurs suddenly (e.g.
flat tire due to abrupt external effects).

Instruments, On-Board Computer, Warnings
145
The tire pressure to be corrected (refill pressure)
is indicated on the displayed wheel.
Example: If “ –1.5 psi (–0.1 bar)” is displayed,
1.5 psi (0.1 bar) must be added to this tire.
Note
The tire pressure menu can only be called up when
the vehicle is stationary.
Calling up the “Info pressure” display
fPush operating lever forward in order to switch
on the selection field.
fSelect “TPM” with the operating lever.
fPush operating lever forward.
The display changes to the tire pressure menu.
fSelect “Info pressure” with the operating lever.
fPush operating lever forward.
Note
After the ignition is switched on, it can take up to
approx. 1 minute before all tire pressures are
displayed. Dashes (“-.-”) appear instead of the tire
pressures. Tire type info in Tire pressure menu
Information about the currently set tires:
– Tire type: Summer tires, winter tires
– Tire size: 18, 19 inch
“Info tires” shows the current tire settings.
Calling up the “Info tires” display
fPush operating lever forward in order to switch
on the selection field.
fSelect “TPM” with the operating lever.
fPush operating lever forward.
The display changes to the tire pressure menu.fSelect “Info tires” with the operating lever.
fPush operating lever forward.
Tire selection in the “Set” menu
fPush operating lever forward in order to switch
on the selection field.
fSelect “TPM” with the operating lever.

148
Instruments, On-Board Computer, Warnings The tire selection has only been successfully
completed when the message “Process
complete” is displayed by the on-board computer.
fSelect arrow (Back) and push the operating
lever forward. The display returns to the tire
pressure menu.
The on-board computer additionally displays
the message “System learning”.Note
The message “Process aborted” appears if the
setting process is interrupted. All entries made up
to this point are lost, and the original settings
remain in effect.
Only if the message “Process complete” appears
after the settings have been made will the Tire
Pressure Monitoring re-learn the wheels.
fPlease see the chapter “SYSTEM LEARNING”
on Page 150.
Before fitting tires with sizes which are not stored
in the on-board computer, the missing information
should be supplemented in the on-board
computer.
fPlease consult your authorized Porsche
dealer.
fUse only tires approved by Porsche.
The available items in the tire pressure menu
depend on the tires on your vehicle. For this
reason it is possible that some of the items shown
here are not available on your on-board
computer’s display.
fMake sure that tire pressures correspond to
the on-board computer settings. Correct the
tire pressure if necessary.
fPlease see the chapter “TIRE PRESSURES FOR
COLD TIRES (68 °F / 20 °C)” on Page 289.Load
fPush operating lever forward in order to switch
on the selection field.
fSelect “TPM” with the operating lever.
fPush operating lever forward.
The display changes to the tire pressure menu.
fSelect “Load” with the operating lever.

230
Maintenance, Car Care fGently wipe the surface without applying too
much pressure.
fDo not clean when dry.
fNever use other chemical cleaners or
solvents.
fRinse cleaned surfaces with clear water.
Leather Characteristics and special features
The natural surface markings of leather, e.g.
creases, healed scars, insect sting marks, struc-
tural differences and slight variations in shade and
grain add to the attractiveness of the natural leath-
er product.
Observe the following care instructions:
Caution!
The leather will be damaged by the use of
unsuitable cleaning and care agents and by
incorrect treatment.
fDo not use caustic cleaners or hard cleaning
aids.
fPerforated leather must under no circumstances get wet on its reverse side.
fClean all types of leather regularly to remove
fine dust using a soft, damp, white woollen
cloth or a commercially available microfibre
cloth.fRemove heavy contamination with a leather
cleaner.
Always read the instructions for use given on
the containers.
We recommend Porsche leather cleaner.
Treat cleaned leather only with a leather care pro-
duct.
We recommend the Porsche leather care product.
Cleaning airbags covers
Danger!
There is a danger of serious personal injury
or death if the airbag system is impaired by
improper cleaning work.
fDo not make any modifications whatsoever on
individual components such as the padded
covers of the steering wheel, passenger side
instrument panel, the front seats and the door
linings.
fLet your authorized Porsche dealer clean these components.
Carpets and floor-mats fUse only a vacuum cleaner or a medium stiff
brush.
fRemove stains and spots with Porsche stain
remover.
To protect carpets, the Porsche range of accesso-
ries includes mats of the correct size and with the
appropriate fastening.
Warning!
Risk of an accident resulting in serious per-
sonal injury or death.
fAlways check the movement of the pedals be-
fore driving and make sure that they are not ob-
structed by a floor-mat or any other object.
fSecure the floor-mat to prevent it from sliding
into positions that could interfere with the safe
operation of your vehicle - do not install them
loosely in the vehicle.
Your Porsche dealer will be glad to offer you nonskid floor-mats of the correct size.
Cleaning fabric liningsfFabric linings on pillars, convertible top liner
and sun blinds, etc. must be cleaned only
using suitable cleaning agents or a suitable dry
foam and a soft brush.

238
Practical Tips, Emergency Service B Vehicle load limit
Is the maximum total weight limit specified of
the load (passengers and cargo) for the vehi-
cle. This is the maximum weight of passengers
and cargo that can be loaded into the vehicle.
Please see the chapter “LOADING INFORMA-
TION” on Page 246.
C Tire size for the front axle
Check with your authorized Porsche dealer
about the current release status.
D Recommended tire pressure for the front axle
These values are for cold tires (68 °F/20 °C).
E Tire size for the rear axle
Check with your authorized Porsche dealer
about the current release status.
F Recommended tire pressure for the rear axle.
These values are for cold tires (68 °F/20 °C).
G In vehicles with collapsible spare wheel:
Size and tire pressure of the spare wheel.
Tire traction
Warning!
When driving on wet or slushy roads, a
wedge of water may build up between the
tires and the road. This phenomenon is
known as “hydroplane” and may cause par-
tial or complete loss of traction, vehicle
control or stopping ability.
fReduce speed on wet surface to prevent this. Tire life Tire life depends on various factors, i. e., road
surfaces, traffic and weather conditions, driving
habits, type of tires and tire care.
fInspect your tires for wear and damage before
driving off. If you notice uneven or substantial
wear, wheels might need alignment or tires
should be balanced or replaced.
Tire wear The original equipment tires on your Porsche have
built-in tire wear indicators. They are molded into
the bottom of the tread grooves and will appear as
approximately 1/2 in. (12 mm) bands when the
tire tread depth is down to 1/16 of an in.
(1.6 mm).
When the indicators appear in two or more adja-
cent grooves, it is time to replace the tires. We
recommend, however, that you do not let the tires
wear down to this extent.
Worn tires cannot grip the road surface properly
and are even less effective on wet roads.
Snow tires lose their traction capability when their
tread depth falls below 5/32 in. (4 mm).
In the United States, state laws may govern the
minimum tread depth permissible. Follow all such
laws.

Technical Data
287
Tires, Rims, Tracks 911 Carrera, 911 Carrera S
Tire Rim Rim offset Track
Summer tires*front 235/40 ZR 18 (91Y) 8 J x 18 H2 57 mm 58.5 in./1486 mm
rear 265/40 ZR 18 (101Y) XL 10.5 J x 18 H2 60 mm 60.4 in./1534 mm
orfront 235/35 ZR 19 (87Y) 8 J x 19 H2 57 mm 58.5 in./1486 mm
rear 295/30 ZR 19 (100Y) XL 11 J x 19 H2 67 mm 59.7 in./1516 mm
orfront 235/35 ZR 19 (87Y) 8.5 J x 19 H2 55 mm 58.5 in./1486 mm
rear 305/30 ZR 19 (102Y) XL 11.5 J x 19 H2 67 mm 59.7 in./1516 mm
Snow tiresfront 235/40 R 18 91V M+S 8 J x 18 H2 57 mm 58.5 in./1486 mm
rear 265/40 R 18 97V M+S** 10.5 J x 18 H2 60 mm 60.4 in./1534 mm
orfront 235/35 R 19 87V M+S 8 J x 19 H2 57 mm 58.5 in./1486 mm
rear 295/30 R 19 100V XL M+S 11 J x 19 H2 67 mm 59.7 in./1516 mm
The load capacity coefficient (e.g. “91”) and maximum speed code letter (e.g. “Y”) are minimum requirements.
Snow chainsCan be mounted only on the rear wheels; maximum speed 30 mph (50 km/h).
Use only Porsche authorized fine-link cross-type or edge chains.
Snow chain clearance can be guaranteed only on the tire + rim combination marked** without spacers.
Please see the chapter “SPACERS 911 CARRERA, 911 CARRERA S” on Page 255.
Tire and rim sizesExtensive tests are performed before specific tires and wheels are approved by Porsche. Your Porsche dealer has informa-
tion about approved tires and wheels and is happy to assist you.
If aftermarket tires and/or wheels are installed which are not approved by Porsche, the vehicle’s driveability, stability while
in motion and handling characteristics might be impaired. Since Porsche has no data on such combinations, Porsche cannot
stand behind the safety or durability of these aftermarket combinations.
* 911 Carrera S: Summer tires 19-inch only