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Diagnstico de alineacin para

Camin

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ALINEACIN

DEFINICIN: El proceso por el cual elvehculo y todos las llantas estn viajando enla misma direccin.

Desempea un papel importante en Tire performance

Reducing Tire Costs

Vehicle handling

Driver control

Improving fuel economy

Component life

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8 Components of Alignment

CASTER

CAMBER

KING PIN INCLINATIONTOE

ACKERMAN ANGLE

TURNING RADIUSAXLE PARALLELISM (thrust and scrub)

AXLE SETBACK

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AXLE MISALIGNMENT

1. Drive axle misalignment most frequent

2. Trailer misalignment 2nd most frequent

3. Steer axle misalignment least frequent

1 2 3

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CASTER- Forward or backward tilt ofthe steering axis as viewed from the side

Necessary to provide self aligning forces on steer tires

Assists in turning wheels to straight ahead positionwhen going around corner

Stabilizes vehicle when:

braking

accelerating

Gives directional stability

Decrease susceptibility to crosswinds

Helps offset effects of road crown

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CASTER PROBLEMS

INSUFFICIENT CASTERReduces stability

Vehicle wanders

EXCESSIVE CASTER

Increases steering effort

Can cause a shimmy

Can cause shoulder wear on tires in city operation

INCORRECT CASTER CAUSED BY:Incorrect shims or installed improperly

Sagging springs

Worn shackles and bushings

Twisted axle

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CAMBER- INWARD OR OUTWARD TILT OF THEWHEELS WHEN VIEWED FROM THE FRONT OF THE

VEHICLE

NECESSARY TO :

REDUCE SIDE THRUST

COMPENSATE FOR WEAR ON STEERING KNUCKLECOMPENSATE FOR WEAR ON WHEEL BEARINGS

SHIFT WEIGHT TO INNER WHEEL BEARING

BUILT INTO AXLES - NON ADJUSTABLE

TRUCK WILL LEAD TO THE SIDE WITH MOSTPOSITIVE CAMBER.

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INCORRECT CAMBER

INCORRECT CAMBER CAN CAUSE:

EXCESSIVE TIRE WEARWANDER (PULLS TO SIDE WITH MOST POSITIVE CAMBER)

HARD STEERING

EXCESSIVE TIRE HEAT

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KINGPIN INCLINATION-The amount, in degrees,that the top of the kingpin inclines away from the vertical as

viewing from the front of the truck.

Kingpin Inclination workingtogether with camber angle arecalled Included Angle. IncludedAngle puts the approximate centerof the tire tread in contact with theroad. Kingpin Inclination has theeffect of reducing steering effortand improves directional stability.

Preferred tolerance is 1 degreefrom side to side. Can be used tohelp determine if an axle or spindle

is bent.

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TOE - The inward or outward pointing of the wheelswhen viewed from the top of the vehicle.

Necessary to compensate for tendency of wheelsto deflect rearward when loaded or in motion.

Goal - zero toe when loaded and in motion

Incorrect toe shows up as feathering of tread onboth ends of axle - greatest tire wear problem

Preferred Specs. For radial tiresare .03 to .07 (1/32 to 1/16)

toe-in.

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A feather or saw tooth edgepointing inward will indicateexcessive toe-in

A feather or saw tooth edgepointing outward willindicate a toe-out problem.

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ACKERMAN ANGLE (TOE OUT ON

TURNS)

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CHECKING ACKERMAN ANGLE

Measure WT (width of tires) and WB(wheel base)

Read intersection of WT and WB

Turn outside wheel to 20 degrees, and readturn table dial on opposite side to verify

proper toe out on turns

Preferred Tolerance +/- 2 deg. forOver the road and +/- 1 deg. Forcity

Note: readings from left to rightshould be within 1 degree.

Correction: replace ackerman arm

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AXLE SETBACK

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AXLE PARALLELISM -All axles should beperpendicular to the frameand parallel with each other

(Steer, drive, and trailer)The rear axles are whatdetermine the direction thevehicle is going to travel.

Rear axle misalignmentresult in excessive tire wearon front and rear axles.

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Thrust Angle - axles notperpendicular to frame but are

parallel to each other.

Tends to push vehicle off course

Driver feels pulling

Steer axle tires feather in samedirection

Drive tires show I/W

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Scrub Angle - Axles NOT perpendicular tothe frame and not parallel to each other.

Constant pull in one directionNeed to continually steer against pull

Drives scrub as vehicle is forced to gostraight

Also affects steer tires

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Trailer Thrust will cause DogTracking

Easily visible in tractor mirrorsEffects all tires on tractor andtrailer

Vehicle wanders

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AXLE PARALLELISM IS CORRECTABLE

SOURCES:

Uneven axle springs

Broken leaf springs

Worn springs

Loose U bolts

Bent frame

Adjustment of torque rods /axlesWorn torque rod bushings

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DRAG LINK ANGLE

Parallel to mid-point of spring mounting +/- 15 degreesupward or downward

EFFECT: Bump steer or directional change - steeringstability - no set wear pattern

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Four Damage Conditions

Twist

Side Sway

SagDiamond

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Side Sway

SIDE SWAY

Frame is bentto the side.

Kenworth says if theframe is bent laterally

enough to cause tirewear and handlingissues then the framerails must be replaced.

If someone were to tryand correct the framethen Side Sway should

be corrected first.

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Sag

SAGThe frame is bent

down in the middle.

Kenworth says that ifbent, Frame rails shouldbe replaced- notrepaired.

If someone were tryingto correcting a bentframe rail then Sagwould be corrected after

side sway and before aTwist or Diamond

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Twist

TWISTThe vehicles front

end rolls to one sideand the rear rolls to

the opposite end.

Twist is generally caused by bentcross members. Locate thestrongest Cross members (fromback of cab to back of frame) -they are the ones that usually holdin the twist

Twist normally will show up in thefront because of lighter springs -but is actually held in the back.

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Diamond

DIAMOND

One frame rail has

moved ahead of the

other frame rail.

Caused by bent Crossmembers.

Occurs most often todaywhen a vehicle is hitdirectly on the frame railfront or rear or most likely

if the vehicle has beentowed or pulled on oneframe rail.

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TRUCK ALIGNMENT

RENTON ASSEMBLY

PLANT

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ALLWHEELALIGNMENT

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CHECK RIDE HEIGHT

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ZERO TO FRAME

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CHECK PINION ANGLE

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LATERALOFFSET

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SWAY BARBUSHING GAP

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CHECKTHRUSTBUSHINGS

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CHECKVEHICLELEAN

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INSTALLHEADS

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RUNOUT

COMPENSATION

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CHECKTHRUSTANGLE

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PERFORM AXLE SWEEP

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CENTER

WHEELSAND SET

TOE-IN

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SET UP TO

CHECK REARAXLE SCRUB

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SCRUB ANGLE

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CHECK TURNING RADIUS

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SET AXLE STOPS

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ADJUST BRAKES

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CHECK STEEING SHAFT

ALIGNMENT