tire type PORSCHE 911 CARRERA 2003 4.G Owners Manual

OperationoftheABSsystem
Awheelspeedsensorismountedtoeachofthe
fourwheels.Ifwheellock-upofeitherofthe
frontwheelsortherearwheelsissensedduring
braking,thebrakepressureisadjustedautomat-
icallyuntilthewheelnolongerslips.Thebrake
pressureisregulatedforeachfrontwheelindi-
viduallyandforbothoftherearwheels
together.
Onaroadsurfacewhichisslipperyononlyone
side,therearwheelwhichisbrakingontheslip-
perysurfacedeterminesthebrakepressure
whichwillbeappliedequallytobothrearwheels.
Thisensuresthatdirectionalstabilityismain-
tained.However,ifbrakingforcesapproachthe
wheellock-uppointforallwheels(panicbraking)
theABSsystemwillintervenetoprovidearapid
rythmicbraking.
TheproperoperationofABSisperceivedbythe
driverasapulsatingbrakepedalinconjunction
withaudiblenoiseandperhapssomevibration.
I>Ifyouexperiencethesesensationswhiledriv-
ingoraroadsurfacewithquestionabletrac-
tion,reducevehiclespeedappropriateforthe
prevailingroadconditions.
Thefunctionalreadinessofallthemainelectrical
componentsoftheABSischeckedbyanelec-
tronicmonitoringsystembothbeforeandwhile
youdrive.

8
WarninglightUSA
@
WarninglightCanada

WhentheignitionisswitchedontheABSwarn-
inglightwilllightupwhilethesystemiselec-
tronicallyinterrogatedandgoesoutwhenthe
engineisstartedifthecheckisnotyetcom-
plete.
IftheABSwarninglampfailstogoout,thisindi-
catesthatABShasbeendeactivatedduetoa
fault.Ifthewarninglightsintheinstrumentpanel
andon-boardcomputerlightupwhileyouare
driving,thisindicatesthatafaulthasoccurred.
Inbothcases,normalbraking,asinvehicles
withoutABS,isstillretained.
TheABSsystemshould,however,beexamined
atanauthorizedPorschedealerimmediatelyto
preventtheoccurrenceoffurtherfaults.
I>IftheABSsystembecomesinoperative,take
yourvehicletoyourauthorizedPorsche
dealerimmediately.
/!\Warning!
ThecontrolunitoftheABSbrakesystemis
setforstandardtiresize.Ifnon-standard
tiresareinstalled,thecontrolunitmaymis-
interpretthespeedofthevehicle,because
ofthevariantdataitreceivesfromthesen-
sorsontheaxles.
I>Useonlytiremakesandtypestestedby
Porsche.
Controls,Instruments
57

Temperature
A,B,C
ThetemperaturegradesareA(thehighest),B
andC,representingthetire'sresistancetothe
generationofheatanditsabilitytodissipate
heatwhentestedundercontrolledconditionson
aspecifiedindoorlaboratorytestwheel.
Sustainedhightemperaturescancausethema-
terialofthetiretodegenerateandreducetire
life,andexcessivetemperaturecanleadtosud-
dentirefailure.
ThegradeCcorrespondstoalevelofperfor-
mancewhichallpassengercartiresmustmeet
undertheFederalMotorVehicleSafetyStandard
No.109.
GradesBandArepresenthigherlevelsofper-
formanceonthelaboratorytestwheelthanthe
minimumrequiredbylaw.
A
Warning!
Thetemperaturegradeforthistireisestab-
lishedforatirethatisproperlyinflatedandnot
overloaded.
Excessivespeed,underinflation,orexcessive
loading,eitherseparatelyorincombination,can
causeheatbuildupandpossibletirefailure.
Tirepressures
A
Warning!
Incorrecttirepressurecausesincreased
tirewearandadverselyaffectsroadhand-
ling.
I>Alwaysuseanaccuratetirepressuregauge
whencheckinginflationpressures.
I>Donotexceedthemaximumtirepressure
listedonthetiresidewall.(Alsoreferto"Tech-
nicaldata").
I>Coldtireinflationpressuremeans:alltires
mustbecold,ambienttemperaturemaximum

68°F
(20°C),whenadjustingtheinflation
pressure.
Avoidsunlightstrikingthetiresbefore
measuringcoldpressures,sincethepress-
ureswouldrisefromtemperatureinfluence.
I>Valvecapsprotectthevalvefromdustand
dirt,andthusfromleakage.
Alwaysscrewcapstightlydown.
Replacemissingcapsimmediately.
I>Forsafetyreasons,don'tusetireinflating
bottles.

Tiretraction

A
Warning!
Whendrivingonwetorslushyroads,a
wedgeofwatermaybuild
up
betweenthe
tiresandtheroad.Thisphenomenonis
knownas"hydroplane"andmaycausepar-
tialorcompletelossoftraction,vehicle
controlorstoppingability.
I>Reducespeedonwetsurfacetopreventthis.

Tirelife

Tirelifedependsonvariousfactors,i.e.,road
surfaces,trafficandweatherconditions,driving
habits,typeoftiresandtirecare.
I>Inspectyourtiresforwearanddamagebe-
foredrivingoff.Ifyounoticeunevenorsub-
stantialwear,wheelsmightneedalignmentor
tiresshouldbebalancedorreplaced.
I>I>I>
PracticalTips,EmergencyService
199

Tiredamage,puncture

I>Checktiresforimbeddedmaterial,cuts,punc-
tures,cracksandbulges(sidewall)before
drivingoff.
Incaseoftiredamage,whereitisuncertain
whetherthereisabreakintheplywithallits
consequencesortiredamagecausedbyther-
malormechanicaloverloadingduetolossof
pressureoranyotherpriordamage,werecom-
mendthatthetirebereplacedforsafetyrea-
sons.
Ifonefaultytireisreplaceditshouldbenoted
thatthedifferenceintreaddepthononeaxle
mustnotexceed30%.
Handlinginconsistenciesmayresult.
I>Performavisualinspectionifnecessary.

Tirereplacements

Ifindoubt,contactyourPorschedealeror
PorscheImporterofyourcountry.
Useonlytiremakesandtypestestedby
Porsche.

IfyoudonotuseaPorscherecommended
replacementtire,makesurethatyoupur-
chaseyournewtiresfromareputabletire
dealerandthatthedealercomplieswithall
manufacturerswarningsforthosetires.
Onlytireswiththesamemakeandwiththe
samespecificationcode(e.g."NO","Nl"...)
canbemounted.
Beforemountingnewtires,checkwithyour
Porschedealeraboutthecurrentrelease
status.
Usetireswith"ZR"qualitystandards.
There
arecurrentlynostandardsconcerningtire
strengthatspeedsabove150mph
(240
kmjhJ.
Tiresshouldbereplacednolessthanononeaxleat
thetime.
Onlytiresofthesamemakeandtypemustbeused.
Mixedtiresarenotpermissible.
Initially,newtiresdonothavetheirfulltraction.
Youshouldthereforedriveatmoderatespeeds
duringthefirst
60-120
miles(100-200kmJ.
Ifnewtiresareinstalledonlyononeaxle,ano-
ticeablechangeinhandlingoccursduetothe
differenttreaddepthoftheothertires.
Thishappensespeciallyifonlyreartiresarere-
placed.However,thisconditiondisappearsas
thenewtiresarebrokenin.
I>Pleaseadjustyourdrivingstyleaccordingly.
Installationofnewtiresshouldonlybedoneby
aqualifiedtiretechnician.

Valves

Rubbervalvestemsmustbereplacedevery
timeatireisreplaced.
Forsteelvalves,theinstallationandreplacement
instructionsmustbeobserved.
UseonlygenuinePorschesteelvalves.

Parkingatthecurb
A
Warning!
Hardimpactsagainstcurbs(ortraffic
islands)aredangerousandmaycausehid-
dentiredamagewhichisnotnoticeable
untillater.Suchdamagecanresultinacci-
dentsathighspeedscausingsevereper-
sonalinjury.
Dependingontheforceofimpact,theedge
oftherimcanalso
bedamaged.
I>Ifyouareindoubt,havethewheelchecked
byanexpert,particularlyifyoususpectdam-
ageontheinside.
I>Ifyoumustdriveoveracurborotherob-
stacle,driveslowlyandatanobtuseangle.
Exercisecarewhenparkingalongcurbs.
PracticalTips,EmergencyService
201

Tire
andrimsizesExtensivetestsareperformedbeforespecifictiresandwheelsareapprovedbyPorsche.
YourPorschedealerhasinformationaboutapprovedtiresandwheelsandishappytoassistyou.
Ifaftermarkettiresand/orwheelsareinstalledwhicharenotapprovedbyPorsche,thevehicle'sroadabilityandhandling
characteristicsmightbeimpaired.SincePorschehasnodataonsuchcombinations,Porschecannotstandbehind
thesafetyordurabilityoftheseaftermarketcombinations.
SnowchainsCanbemountedonlyontherearwheels;maximumspeed30mph/50km/h,
UseonlyPorscheauthorizedfine-linkcross-typeoredgechains.
Snowchainclearancecanbeguaranteedonlyonthetire+rimcombinationmarked*,
Sparewheel911Carrera:T105/95R17high-pressuretireon3.5Jx17rim.
911Carrera4,Carrera4S:165/70R1692Pcollapsibletireon5.5Jx16rim.
Maximumspeed50mph/80km/h,Alwayscomplywiththeinstructionsinthechapter"Sparewheel",
248TechnicalData

Tire
Pressuresforcoldtires
Summertiresandsnowtires
Front17inchwheels:
18inchwheels:
36psi(2.5bar)overpressure
36psi(2.5bar)overpressure
Rear17inchwheels:
18inchwheels:
36psi(2.5bar)overpressure
44psi(3.0bar)overpressure

Spare
wheel911Carrera
Frontandrear60psi(4.2bar)overpressure
Collapsiblesparewheel911Carrera4,Carrera4S
Frontandrear36psi(2.5bar)overpressure
ThesetirepressuresapplyonlytothetiremakesandtypesapprovedbyPorsche.
Alwaysobserveinstructionsinthechapter"TiresandTireCare",
TechnicalData
249