2009 PORSCHE 911 tire type

62
Operation, Safety When the ignition is switched on the ABS warning
light will light up while the system is electronically
interrogated and goes out when the engine is
started if the check is not yet complete.
If the ABS warning lamp fails to go out, this indi-
cates that ABS has been deactivated due to a
fault. If the warning lights in the instrument panel
and on-board computer light up while you are driv-
ing, this indicates that a fault has occurred. In both
cases, normal braking, as in vehicles without ABS,
is still retained.
The ABS system should, however, be examined at
an authorized Porsche dealer immediately to pre-
vent the occurrence of further faults.
fIf the ABS system becomes inoperative, take
your vehicle to your authorized Porsche dealer
immediately.
Warning!
Risk of an accident, resulting in serious per-
sonal injury or death.
The control unit of the ABS brake system is
set for standard tire size. If non-standard
tires are installed, the control unit may mis-
interpret the speed of the vehicle, because of
the variant data it receives from the sensors
on the axles.
fUse only tire makes and types tested by Porsche.
Clutch Pedal The clutch pedal must be depressed fully
before the starter will engage.
Warning!
Risk of an accident, resulting in serious per-
sonal injury or death.
fAlways check the movement of the clutch ped-
al before driving and make sure that it is not
obstructed 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.
Your Porsche dealer will be glad to offer you
nonskid floor mats of the correct size.
To avoid damage to the clutch and transmis-
sion:
fAlways depress the clutch pedal fully when
changing gears.
fDo not hold the car on a steep grade with the clutch pedal partially depressed.
Should the free travel of the clutch pedal suddenly
become larger, it could mean a malfunction of the
clutch.
fSee your Porsche dealer for correction.
Warning light USA
Warning light Canada

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.

146
Instruments, On-Board Computer, Warnings fPush operating lever forward.
The display changes to the tire pressure menu.fSelect “Set” with the operating lever.fPush the operating lever forward.
fSelect desired tire type:
summer or winter.
fPush operating lever forward.
A display for confirming the selected type of
tire appears.

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.

240
Practical Tips, Emergency Service
Danger!
Risk of serious personal injury or death.
Driving the vehicle with low tire pressure
increases risk of a tire failure and resulting
loss of control. Furthermore, low tire pres-
sure increases rate of wear of the affected
tires.
fCheck tires – including sidewalls – regularly for
foreign bodies, nicks, cuts, cracks and bulges.
fAfter driving off road, examine tires for signs
of damage such as cuts, tears, bulges or for-
eign objects stuck in the tread. Replace a dam-
aged tire if necessary.
fCross curb edges slowly and at right angles if
possible.
Avoid driving over steep or sharp curbs.
fIn cases of doubt, have the wheel (particularly
the inner side) checked by an authorized Porsche dealer.
Tire replacements If in doubt, contact your Porsche dealer.
Use only tire makes and types approved by
Porsche.
If you do not use a Porsche recommended
replacement tire, make sure that you
purchase your new tires from a reputable tire
dealer and that the dealer complies with all
manufacturers warnings for those tires.
Only tires with the same make and with the
same specification code (e.g. “N0”, “N1”...)
can be mounted.
Before mounting new tires, check with your
Porsche dealer about the current release
status.
Use tires with “ZR” quality standards. There
are currently no standards concerning tire
strength at speeds above 150 mph (240 km/h).
Tires should be replaced no less than on one axle
at the time.
Only tires of the same make and type must be
used. Mixed tires are not permissible.
Initially, new tires do not have their full traction.
You should therefore drive at moderate speeds
during the first 60 - 120 miles (100 - 200 km). If new tires are installed only on one axle, a notice-
able change in handling occurs due to the different
tread depth of the other tires.
This happens especially if only rear tires are re-
placed. However, this condition disappears as the
new tires are broken in.
fPlease adjust your driving style accordingly.
Installation of new tires should only be done by a
qualified tire technician.
Valves
Rubber valve stems must be replaced every time
a tire is replaced.
For metal valves, the installation and replacement
instructions must be observed.
fUse only genuine Porsche metal valves.
fProtect the valve inserts against soiling with
valve caps.
Soiled valve inserts can cause a gradual loss
of air.
fUse only plastic valve caps.

244
Practical Tips, Emergency Service
Example of InscriptionInscription on radial tireATire size
Example: P 295/30 ZR 19 100 Y
–P - The tire is designed for Passenger vehicle.
This information is not included on all tires.
–295 - Indication of tire width in mm
–30 - Indication of tire height to tire width ratio
in percent–ZR - code letter for radial tires for speeds
above 150 mph / 240 km/h
There are currently no standards concerning
tire strength at speeds above 150 mph
(240 km/h).
–R - Belt type code letter for radial
–19 - Indication of rim diameter in inches
–100 - Load capacity coefficient
–Y - Speed code letter
–XL (Extra Load) - Tire with increased load rat-
ing
B TIN (Tire Identification Number)
Example: DOT xx xx xxxx xxxx
–DOT
The DOT symbol indicates that the tires com-
ply with the requirements of the US Depart-
ment of Transportation and provides informa-
tion about:
– first two-digit code means manufacturer’s iden-
tification mark.
– second two-digit code means tire size.
– third four-digit code means tire type code.
– fourth four-digit code means date of manufac-
ture.
If, for example, the last four numbers read
0204, the tire was produced in the 2nd week
of 2004.
C Tire ply composition and material
The number of layers in the tread and sidewalls
and their material composition.
D Maximum permissible inflation pressure
The maximum permissible cold inflation pressure
to which a tire can be inflated.
fDo not exceed the permissible inflation
pressure.