technical specifications PORSCHE 911 2009 5.G Owners Manual

152
Instruments, On-Board Computer, Warnings
No monitoringIn the event of faults the Tire Pressure Monitoring
cannot monitor the tire pressure.
The warning light in the speedometer flashes for
approx. one minute and then remains continuously
illuminated and a corresponding message
appears on the on-board computer.
Monitoring is not active when:
– the Tire Pressure Monitoring is faulty,
– wheel transmitters for the Tire Pressure
Monitoring are missing,
– during the learning phase after the tire settings
have been updated,
– after a wheel change without updating the tire
settings,
– more than four wheel transmitters are
detected,
– there is external interference by other radio
sources, e.g. wireless headphones,
– tire temperatures are too high.
fPlease see the chapter “WARNINGS ON THE
INSTRUMENT PANEL AND THE ON-BOARD
COMPUTER” on Page 158.
Pressure increase as the result of
temperature increaseIn accordance with physical principles, the air
pressure changes as the temperature changes.
The tire pressure increases or decreases by
around 1.5 psi (0.1 bar) for every 18 °F (10 °C)
change in temperature.
The Tire Pressure Monitoring takes this relation-
ship between tire pressure and temperature into
account.Tire pressure specificationsInformation on tire pressure for public roads can
be found in this Owner's Manual in the Technical
Data chapter or on the tire-pressure plate in the
left door aperture.
These values apply to cold tires at 68 °F (20 °C)
ambient temperature.

Practical Tips, Emergency Service
235
Tires/Wheels The original equipment tires and wheel rims on
your Porsche comply with all applicable Federal
Motor Vehicle Safety Standards.
For your safety remember the following:
– Wheel rims and wheel bolts are matched to fit
your Porsche.
– If you intend to use other than original equip-
ment wheels, be sure that they conform to
Porsche specifications for your model.
Only tires with the same make and with the
same specification code (e.g. “N0”, “N1”...)
can be mounted.
– The use of wheel rims and wheel bolts that do
not meet specifications of the original factory
installed equipment will affect the safe opera-
tion of your vehicle.
– Before you plan on exchanging wheels, or
snow tires already mounted on the wheel rims,
consult your authorized Porsche dealer. Your
dealer has the technical information necessary
to advise you which wheel rims and wheel bolts
are compatible with the original factory instal-
lations.
Danger!
Risk of loss of control and serious personal
injury or death.
fIf while driving, your vehicle experiences a sud-
den vibration or ride disturbance, and/or you
suspect that possible damage to your tires or
vehicle has occurred, you should immediately
reduce your speed without excessive use of
the brakes.
fStop the vehicle as soon as possible, and in-
spect the tires.
If you cannot determine the cause for the dis-
turbance, have your vehicle towed to the near-
est Porsche or tire dealer to have your vehicle
or tire(s) inspected.
fContinuing to operate the vehicle without cor-
rection could result in a loss of control and serious personal injury.
ExampleUniform Tire Quality GradingQuality grades can be found where applicable on
the tire sidewall between tread shoulder and max-
imum section width.
All passenger car tires must conform to Federal
Safety Requirements in addition to these grades.
Tr e a d w e a r
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specific govern-
ment test course.
For example, a tire graded 150 would wear one