Navistar International LT Series - Checking Inflation; Underinflation; Inspection

MaintenanceInstructions
CheckingInation
Alwayscheckinationpressurewhentiresarecold.Neverbleed
airfromhottirestorelievenormalpressurebuildup.Normal
increasesinpressureduringoperationwillbe10-15psi(69
-103kPa),whichisallowableintrucktires.Tiresonthesame
axleshouldhavethesameairpressureasthecorresponding
othertire(s)onthataxle.Steertiresshouldbewithina3psi
(21kPa)pressurerangeofeachother.Alldrivetiresshouldbe
withina5psi(34kPa)pressurerangeofeachother.
Underination
Tiresshouldnotbeallowedtobecomeunderinated.Increased
exingduetounderinationcausesheatbuildupwithinthe
tirecomponents.Thisleadstoreducedstrength,breakdown
oftherubbercompounds,andpossibleseparationofthetire
components(suchasplyandtreadseparationandreduced
retreadability).
Underinationisalsotheprimarycauseofblowouts.Inaddition,
lowinationcausesanincreaseinrollingresistance.Thisresults
inreducedfuelmileage,alossintreadlife,andunevenwear
duetoincreasedtreadmovement.Todetermineproperination,
refertothetireinationrangestatedonthetiresidewallandthe
tiremanufacturer’stireload-pressurecharts.
Inspection
Checkconditionoftiresforabnormalwearpatternsandproper
inationpressures.Cutorbrokentirecasingsmustberepaired
orreplaced.
Tiresshouldbeinspectedforthefollowingconditions.Ifanyare
present,thetireshouldberemovedandrepaired,retreaded,or
scrappedastheconditionindicates.
•Anyblister,bump,orraisedportionanywhereonthe
surfaceofthetiretreadorsidewall(otherthanabump
madebyarepair).Theseindicatethestartofinternal
separation.
•Anycutthatreachestothebeltorplycordsoranycut
thatislargeenoughtogrowinsizeanddepth.
•Anynailorpuncturingobject.
•Ifanystoneorobjectisheldbyatreadgrooveandis
startingtodrillintothetreadbase,removetheobject.
Propertireination,toe-inadjustment,loads,androad
speedsareimportantfactorsgoverningtirelife,steeringease,
maneuverability,fueleconomy,andridequality.
NOTE:Yourvehicleisequippedwithafactorypreset
limitingthevehicle’sroadspeednottoexceedthatof
thetireratingsasinstalledbythefactory.Intheevent
youshouldchange/replacevehicletireswiththoseofa
lowerroadspeedrating,itwillbenecessaryforyoutotake
yourvehicletothedealertohavethereadspeedengine
parameterchangedtomatchthenewtirerating.
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