PORSCHE 911 CARRERA 2005 5.G Owners Manual

Practical Tips, Emergency Service
211
Traction AA, A, B, C
The traction grades, from highest to lowest, are
AA, A, B, and C and they represent the tire’s ability
to stop on wet pavement as measured under con-
trolled conditions on specified government test
surfaces of asphalt and concrete.
A tire marked C may have poor traction perform-
ance.
Warning!
The traction grade assigned to this is based on
braking (straight-ahead) traction tests and does
not include cornering (turned) traction, accelera-
tion, hydroplaning or peak traction characteris-
tics. Temperature A, B, C
The temperature grades are A (the highest), B and
C, representing the tire’s resistance to the gener-
ation of heat and its ability to dissipate heat when
tested under controlled conditions on a specified
indoor laboratory test wheel.
Sustained high temperatures can cause the mate-
rial 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 perform-
ance which all passenger car tires must meet un-
der the Federal Motor Vehicle Safety Standard No.
109.
Grades B and A represent higher levels of per-
formance on the laboratory test wheel than the
minimum required by law.
Warning!
The temperature grade for this tire is established
for a tire that is properly inflated and not overload-
ed.
Excessive speed, underinflation, or excessive
loading, either separately or in combination, can
cause heat buildup and possible tire failure.

212
Practical Tips, Emergency Service
Tire pressures
Warning!
Incorrect tire pressure causes increased tire
wear and adversely affects road handling.
fAlways use an accurate tire pressure gauge
when checking inflation pressures.
fDo not exceed the maximum tire pressure list-
ed on the tire sidewall.
Please observe the chapter “TIRE PRESSURE
PLATE” on Page 263.
fCold tire inflation pressure means: all tires
must be cold, ambient temperature maximum
(68°F/20°C)
, when adjusting the inflation pres-
sure.
Avoid sunlight striking the tires before measur-
ing cold pressures, since the pressures would
rise from temperature influence.
fValve caps protect the valve from dust and dirt,
and thus from leakage.
Always screw caps tightly down.
Replace missing caps immediately.
fUse only plastic valve caps.
fDo not use commercially available sealant or
tire inflating bottles. Only use Porsche approved tire sealant.The tire pressure must match the prescribed val-
ue.
You can find information on tire pressure:
– on Page 5 of this Owner’s Manual
– and in the left door aperture.
These values are for cold tires (68°F/20°C).
fCheck the tire pressure at least every
2 weeks. Always check when tires are cold.
When tires are warm, the tire pressure is
increased.
fNever let air out of hot tires.
This could cause the tire pressure to fall below
the prescribed value.
Insufficient tire filling pressure can cause tires to
overheat and thus be damaged – even invisibly.
Hidden tire damage is not eliminated by subse-
quently correcting the tire pressure.Overloading
Danger!
Risk of personal injury, loss of control and
damage to vehicle parts.
fDo not overload your vehicle. Be careful about
the roof load.
fIf loading the vehicle also correct the tire pres-
sure. Tire pressure for loaded vehicle can be
found on the tire pressure plate and in the
chapter technical data.
fNever exceed the specified axle load.
Overloading can shorten the service life of the
tires and car, as well as lead to dangerous ve-
hicle reactions and long braking distances.
Damage due to overloading is not covered by the vehicle warranty.
fPlease observe the chapter “LOADING INFOR-
MATION” on Page 222.
fPlease observe the chapter “TIRE PRESSURES
FOR COLD TIRES” on Page 267.

Practical Tips, Emergency Service
213
Example of a tire pressure plate ATire pressure plateDepending on when your vehicle was manufac-
tured, the tire pressure plate on the driver's door
aperture will contain different data.
Information on the tire pressure plate A
A Seating capacity
Maximum number of vehicle occupants, includ-
ing the driver.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.
If a trailer is being towed, the trailer tongue
weight must be included as part of the cargo
load.
Please observe the chapter “LOADING INFOR-
MATION” on Page 222.
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
Example of a tire pressure plate BInformation on the tire pressure plate B
A Information for tire sealant, seating capacity,
vehicle load limit
B Approved tire size for the front axle
C Permissible tire pressure for the front axle
D Tire pressure for fully loaded or partially
loaded vehicle
E Permissible tire pressure for the rear axle
F Approved tire size for the rear axle

214
Practical Tips, Emergency Service
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.
In the United States, state laws may govern the
minimum tread depth permissible. Follow all such
laws.
Danger!
Driving on worn tires can result in loss of con-
trol of the vehicle and could cause serious
personal injuries or death.
fDo not drive with worn tires or tires showing
cuts or bruises as they may lead to sudden
deflation and loss of control which could cause
severe personal injury.
fSpecialized high performance tires on high
performance sports cars exhibit more wear
than those on a family sedan, or even a high
performance sedan.
Therefore, it is important to check your tire
pressure and condition at least every two weeks.
If you notice that tires are wearing unevenly, con-
sult your Porsche dealer.
Uneven wear may not always be due to improper
wheel alignment. It can be the result of individual
driving habits such as cornering at high speeds. If
the tire pressure is not checked and adjusted
regularly, abnormal tire wear can also occur.

Practical Tips, Emergency Service
215
Tire care fAvoid damaging tires and wheel rims.
fIf you must drive over a curb or other obstacle,
drive slowly and at an obtuse angle.
fCheck tires for uneven wear and damage
before driving off.
fRemove imbedded material.
fReplace worn or damaged tires immediately.
fKeep oil, fuel, brake fluid, etc. away from tires.
fReplace missing valve stem caps.
fKeep tires inflated correctly.
fWash tires when washing the vehicle. Also
clean inner side of wheels.
fDo not use abrasive cleaners when washing
the wheels.
fCheck wheel rims for corrosion.
fRemove road salt, if driving in winter.
Tire damage, puncture fCheck tires for imbedded material, cuts, punc-
tures, cracks and bulges (side wall) before driv-
ing off.
In case of tire damage, where it is uncertain wheth-
er there is a break in the ply with all its conse-
quences or tire damage caused by thermal or me-
chanical overloading due to loss of pressure or
any other prior damage, we recommend that the
tire be replaced for safety reasons.
If one faulty tire is replaced it should be noted that
the difference in tread depth on one axle must not
exceed 30%.
Handling inconsistencies may result.
fPerform a visual inspection if necessary.
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.

216
Practical Tips, Emergency Service
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.
Parking at the curb
Warning!
Hard impacts against curbs (or traffic
islands) are dangerous and may cause hid-
den tire damage which is not noticeable until
later. Such damage can result in accidents at
high speeds causing severe personal injury.
Depending on the force of impact, the edge
of the rim can also be damaged.
fIf you are in doubt, have the wheel checked by
an expert, particularly if you suspect damage
on the inside.
fIf you must drive over a curb or other obstacle,
drive slowly and at an obtuse angle. Exercise care when parking along curbs.

Practical Tips, Emergency Service
217
Wheel alignment, wheel balancing As a precaution, have wheels with summer tires
balanced in the spring, and those with mud and
snow tires before winter.
Unbalanced wheels may affect car handling and
tire life.
Only the specified weights may be used for wheel
balancing.
Self-adhesive weights must not come into contact
with cleaning agents, since they could drop off.
Uneven tread wear indicates wheel imbalance. In
this event, the vehicle should be checked at an au-
thorized Porsche dealer.
Warning!
If, during a journey, uneven running or vibra-
tions occur that could be caused by damage
to tires or the car, the speed must be re-
duced immediately, but without braking
sharply.
If you continue your trip without having the
cause of the fault remedied, you might lose
control of your vehicle which could cause se-
vere personal injury.
fStop the vehicle and check the tires.
fIf no cause for the fault can be found, drive
carefully to the nearest authorized Porsche dealer.
Removing and storing tires fAfter changing, adjust tire pressure and torque
wheel bolts diagonally to 94 ftlb (130 Nm).
Tires must always remain on the same side of
the vehicle.
When wheels are removed, the direction of
rotation and position of each wheel should be
marked.
Example
FR (front right), FL, RR and RL.
Wheels must always be fitted in accordance with
their marking.
The preception that tire durability and perform-
ance are immune to the effects of storage and
age is unfounded.
Chemical additives, which make the rubber elas-
tic, lose their effectiveness in the course of time
and the rubber becomes brittle and cracks.
Therefore, the tires should be inspected from
time to time. Note
Under no circumstances should tires older than 6
years be used on your Porsche.
The age of the tire can be obtained from the “DOT”
code number. If, for example, the last four num-
bers read 1204, then the tire was produced in the
12th week of 2004.
fStore tires in a cool and dry place.

218
Practical Tips, Emergency Service
Snow tires For a better grip on snow and ice, use radial M+S
tires with studs.
Check with your local Motor Vehicle Bureau for
possible restrictions.
Danger!
Risk of loss of control and damage to the
vehicle as well as serious personal injury or
death.
The standard tires profile and rubber mixture
are optimized for wet and dry driving condi-
tions, and may not prove favorable for snow
conditions.
fTherefore install M+S tires before driving in such conditions.
Before mounting snow tires, consult with
your Porsche dealer. He has the technical
information necessary to advise you on
wheel and tire compatibility.
Snow tires should have the same load capacity as
original equipment tires and should be mounted on
all four wheels.
Snow tires with studs should be run at moderate
speeds when new in order to give the studs time
to settle.
Danger!
Tires with badly worn treads and studs are
very dangerous and could cause accidents
resulting in serious personal injuries or
death.
fMake sure they are replaced immediately.
fDo not drive a vehicle equipped with snow tires
at prolonged high speed.
Snow tires do not have the same degree of
traction on dry, wet or snowfree roads as a
normal tire.
Furthermore, snow tires wear rapidly under
these conditions. Comply with all state and local laws
governing snow tire and tread depth require-
ments.
Danger!
Risk of accident and serious personal injury
or death due to excessive speed.
fAlways check the maximum speed rating on
the tire sidewall on any tire on the vehicle.
fNever exceed the maximum speed rating of the tires.
fFit winter tires to both axles well before the
cold season begins.
Your authorized Porsche dealer will be pleased
to advise you.
Maintenance note
We recommend fitting winter tires on the vehicle at
temperatures below 45°F (7°C ).
Winter tires lose their traction capability when their
tread depth falls below 5/32 in. (4 mm).

Practical Tips, Emergency Service
219
Snow chains
Caution!
Risk of damage to body, axle or brake com-
ponents.
fFit snow chains only to the rear wheels, and
only with the tire/rim combination listed in the
Technical Data.
To ensure adequate clearance between chain
and body, Porsche recommends only the use
of fine-link chains such as those approved by
Porsche.
fFollow instructions issued by the supplier of the chains.
Different states and countries have varying statu-
tory requirements regarding maximum speed.
Check with local authorities for possible restric-
tions.
fRemove chains as soon as the roads are free
of ice and snow.
Tire designations Due to new speed and load ratings for radial tires,
new designations have come into force for snow
tires for your Porsche.
The designation to be used for ZR tires is e.g.,
265/40 ZR 18 (Z = code letter for radial tires for
speeds above 150 mph / 240 km/h).

220
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 manufacture’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 pres-
sure.