MCCORMICK X60.40 - Ballast and Wheel Slip; Further Notes; Rear Axle Payload

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Safety notes
Further notes
ThefollowingnotesaredesignedtocompletetheOpera-
tionandMaintenanceManualtoensurethatyourtractor
alwaysworkssafely,reliablyandefficiently.
Tractorsaremainlydesignedforhitchingimplementsthat
areheldbyadrawbarorthree-pointlinkageorfordriving
implementsusingthePTO.
Toobtainthegreatestpossibletowingforce,particularly
whenusingatractorwithdualrearwheels,youshould
observe the following rules concerning axle loads and
wheelslip.
Ifanextraimplementisattached,theextraloadsmust
conformtothespecificationsgivenintheManualorby
yourdealer.
1. Front axle payload: 4WD tractors.
 The front axle normally bears 40% of the tractor
weightontheroadwithoutimplements;itmaythus
benecessarytoaddanextraweightonthefrontend
toensurethatthefrontaxlehastraction.
 Ifanimplementismountedonthefrontendofthe
tractor,checktheweightofthefullyloadedimplement
by placing the front axle on a scale: the maximum
axleloadmustbelessthanthecapacityofthefront
axle.
 Check the maximum payload capacity of the front
axle(maximumweightallowedonit)inyourOpera-
tionandMaintenanceManual).
2. Rear axle payload.
 Themaximumpermissiblepayloadfortherearaxle
dependsonwhetherornotthetractoriscarryinga
weightortowingaload.
 Whenthetractorisonlycarryingaload,withouttow-
ing,thewheelsmusthavesufficientcapacitythatis
ensured if the tyres are of the exact size and have
thespecifiednumberofplies.
 Incertainconditions,extraweightmaybeappliedto
therearaxlebutitisnotnormallynecessaryunless
thegroundoffersverylittlegrip.
 Whenfullyloaded,theweightofthetractormustbe
lessthanthemaximumpermissibleballastedweight
since the tractor cannot be loaded right up to the
maximumstaticpayloadforeachoftheaxles,front
and rear, at the same time.
3. Ballast and wheel slip.
 Wheelslipmustbemeasuredforthetractortooper-
ateefficientlyduringtillage.
 Onnormalterrainingoodoperatingconditions,wheel
slipshouldbebetween4and10%.
 Onloosesoil,wheelslipcanexceed12%.
 Ifwheelslipisfoundtobegreaterthanthisamount,
proceed with care as operating conditions might
quicklybecomeunstableandcauseearlytyrewear.
 Incertainconditions,itmightbebettertoaddballast
inordertoreducewheelslip,butthisincreasesthe
workloadofthetransmission and thus reducesthe
workinglifeofthetractor.
 ReadtheoperationhandbookoraskyourDealerwho
willbeabletohelpyouascertainthemaximumballast
weightyoucanuseinnormalworkingconditions.
 Usingdualwheelsorwidertyres,thetractorwillhave
greatergripbuttheworkloadonthetransmissionwill
alsobegreaterindryanddifficultsoilconditions.
 Dual wheels or wider tyres can sometimes be
mountedforuseonslipperyorsandyterrainbutthe
axleweightonhard,drysurfacesmustbelimitedas
thegreatergripprovidedbywidertyrescandamage
thetransmission.
 The only torque limiter in transmission is wheel
slip.
4. Front axle lead when four-wheel drive is en-
gaged.
 Ina4WDtractor,thegroundspeedofthefrontwheels
mustbeslightlygreaterthanthatoftherearwheels,
inordertoensuretraction.
 Thefrontwheeladvancemustbepreferablybetween
1%and4%,atanratenotover5%.
 Greaterpercentagesmaybeusedonlyonverysoft
ground.
 Thetyressuppliedwithyourtractorhavebeenchecked
forthecorrectadvanceofthefrontwheels,butwhen
you change them, make sure you use tyres of the
samemakeand size in ordertomaintainthesame
speedratiobetweenfrontandrearwheels.
 If tyres of different makes are used, their size and
internalpressuremaymodifythisgroundspeedratio,
oradvance.Thiscouldincreasetheloadonthefront
axleandleadtounacceptableoperatingconditions,
excessivetyrewearand,inextremeconditions,dam-
agetothefrontaxleortothetransmission.
 Changesintheweightofthetractor,inthepressure
orsizeofthe tyrescan causethe tyresthemselves
to bounce. This is not only annoying for the driver
inthecab,butitcanalsocausealossofgripand
excessivewearinthetransmissionunit.