tire type PORSCHE BOXSTER 2005 2.G Owners Manual

56
Controls, Instruments
Operation of the ABS system A wheel speed sensor is mounted to each of the
four wheels. If wheel lock-up of either of the front
wheels or the rear wheels is sensed during bra-
king, the brake pressure is adjusted automatically
until the wheel no longer slips. The brake pressure
is regulated for each front wheel individually and
for both of the rear wheels together.
On a road surface which is slippery on only one si-
de, the rear wheel which is braking on the slippery
surface determines the brake pressure which will
be applied equally to both rear wheels. This ensu-
res that directional stability is maintained. Howe-
ver, if braking forces approach the wheel lock-up
point for all wheels (panic braking) the ABS system
will intervene to provide a rapid rythmic braking.
The proper operation of ABS is perceived by the
driver as a pulsating brake pedal in conjunction
with audible noise and perhaps some vibration.
fIf you experience these sensations while dri-
ving or a road surface with questionable trac-
tion, reduce vehicle speed appropriate for the
prevailing road conditions.
The functional readiness of all the main electrical
components of the ABS is checked by an electro-
nic monitoring system both before and while you
drive. 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 star-
ted if the check is not yet complete.
If the ABS warning lamp fails to go out, this indica-
tes 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 driving, 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!
The control unit of the ABS brake system is
set for standard tire size. If non-standard ti-
res are installed, the control unit may misin-
terpret 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.
Warning light USA
Warning light Canada

Maintenance, Car Care
195
Paint fNever rub a dusty car with a dry cloth since
dust particles are abrasive and could dull and
damage the surface finish.
The paintwork of your car is exposed to all types
of mechanical and chemical conditions, particular-
ly climatic ones such as bright sunlight, rain, frost
and snow. Ultraviolet light, rapid changes in tem-
perature, rain, snow, industrial dust and chemical
deposits constantly attack the paint which is only
able to withstand such exposure in the long term
if it is given regular care and attention.
fDo not apply silicone polishes to the winds-
hield, windows or convertible top.
fDo not treat matt-painted components with
preservatives or polishes as this will spoil the
matte effect. Preservation
The paint surface becomes dull over time due to
weathering. It is therefore necessary to preserve
the paint regularly.
This keeps the paint shiny and elastic. Dirt is pre-
vented from adhering to the paint surface and in-
dustrial dust is prevented from penetrating the
paint.
Provided it is washed and treated with preservati-
ve regularly, the brand new finish of your car will
be retained for years to come.
fApply the Porsche paint preservative after the
car wash and polish it dry to obtain a bright fi-
nish or simply add a liquid preservative regular-
ly to the final rinse water and rub down with a
leather chamois.
Polishing
Do not resort to using Porsche polish until it beco-
mes evident that the normal preservatives no lon-
ger produce the desired finish.
Spots and stains
fRemove tar stains, grease, oil spots and dead
insects as soon as possible with Insect Remo-
ver. They can cause discoloration if allowed to
remain on the paintwork.
fWash the affected area immediately after trea-
ting it. Minor paint damage
fHave minor paint damage, such as scratches,
scores or chips caused by flying stones, re-
paired immediately by your authorized
Porsche dealer before corrosion sets in.
However, if there are already traces of corrosion,
they must first be removed carefully and tho-
roughly. Coat the area with a rust-proofing primer
and finish off with a top coat. The paint code and
color number are found on the vehicle’s tire pres-
sure plate.

208
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.

210
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.

214
Practical Tips, Emergency Service
Example of InscriptionInscription on radial tireATire size
Example: P 265/40 ZR 18 101 Y
–P - The tire is designed for Passenger vehicle.
This information is not included on all tires.
–265 - Indication of tire width in mm
–40 - 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
–18 - Indication of rim diameter in inches
–101 - 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.

Vehicle Identification, Technical Data
263
fWhen changing tires or fitting new ones: Please observe the chapter “WHEEL BOLTS” on Page 222.
Danger!
Installation of sizes not authorized by
Porsche may have a dangerous effect on
the driving stability and could result in
severe personal injury or death.
fBefore mounting new tires, check with yourPorsche dealer about the current release status. Boxster S Tires Rim Rim offset Track
Summer tiresfront 235/40 ZR 18 91Y 8 J x 18 H2 57 mm 58.5 in./1486 mm
rear 265/40 ZR 18 101Y XL 9 J x 18 H2 43 mm 60.2 in./1528 mm
or front 235/35 ZR 19 87Y 8 J x 19 H2 57 mm 58.5 in./1486 mm
rear 265/35 ZR 19 94Y 9.5 J x 19 H2 46+ mm 60.0 in./1522 mm
Snow tiresfront 255/40 R 18 91V M+S 8 J x 18 H2 57 mm 58.5 in./1486 mm
rear * 255/40 R 18 95V M+S 9 J x 18 H2 43 mm 60.2 in./1528 mm
The load capacity coefficient (e.g. “91”) and maximum speed code letter (e.g. “Y”) are minimum requirements.
Tire and rim sizes
Extensive tests are performed before specific tires and wheels are approved by Porsche. Your Porsche dealer has information
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 roadability 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.
* Snow chains Can 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 with the tire + rim combination marked.

264
Vehicle Identification, Technical Data
Tire pressure for cold tires fThese tire pressures apply only to the tire makes and types approved by Porsche.
Please observe the chapter “WHEEL BOLTS” on Page 222. Summer and snow tires
17 inch wheels front 29 psi (2.0 bar)
rear 36 psi (2.5 bar)
18 inch wheels front 29 psi (2.0 bar)
rear 36 psi (2.5 bar)
19 inch wheels front 32 psi (2.2 bar)
rear 36 psi (2.5 bar)