Presentation on theme: "Automotive Alignment Angles"— Presentation transcript:
1Automotive Alignment Angles CamberCasterFront toeRear toe
2Primary Alignment Angles Front CamberRear CamberCasterFront ToeRear Toe2 lines meetto form anAngle
30 º ± 1 º -.5 º ± 1 º Camber Definition: Typical Range: The inward or outward tilt of the top of the wheel as viewed from the front.Typical Range:Front camber -Rear camber -0 º ± 1 º-.5 º ± 1 º
4Zero Camber Wheel is vertical when viewed from the front Measured as Zero degreesApplicable to front and rear tires
5Reasons to use at or near Zero Camber Extremely wide tiresPositive offset rimsExtended Tire life
6Positive CamberTop of tire leans outboard at the top when viewed from the frontMeasured in degreesPrimarily used on front wheels
7Reasons to use Positive Camber Places load inboard on spindleIncreases road isolationIncreases directional stability
8Negative CamberTop of tire leans inboard at the top when viewed from the frontMeasured in degreesPrimarily used on rear wheels
9Reasons to use Negative Camber Places load outboard on spindleIncreased cornering abilityIncreases road shock & component wear
10Outside Shoulder Wear due to Excessive Positive Camber Angle
11Camber may cause a PullCross camber is the side-to-side difference in camber measurementsMore than 1/2º difference side-to side may cause the vehicle to pull to the wheel with the most positive camber.
12Excessive Cross Camber Vehicle may pull to side of most positive camber
13Camber Specifications Preferred Specs Front = 0º Rear = -.40ºTolerance Front = 1º Rear = .75ºCross camber .70º
15CasterFrontThe Forward or Rearward Tilt of the Steering Axis as viewed from the sideTypical RangeTypical tolerance ± 1º1º to 6 º positive
16Steering Axis Line drawn between the two pivot points of the steering knuckle
17Zero CasterSteering Axis is vertical as viewed from the side and measured as 0º
18Negative CasterForward tilt of the Steering Axis as viewed from the side and measured in degreesFront
19Positive CasterRearward tilt of the Steering Axis as viewed from the side and measured in degreesFront
20Benefits of Positive Caster Helps to return wheels to straight ahead after being steeredHelps to maintain directional stabilityWeight must be picked up as spindle turns downward ….
21Negative effects of Excessive Positive Caster Excessive steering effort & road shockShimmy due to excessive speed of wheels returning to centerSteering damper used to control speed of steered wheels returning to centerDampner
22Caster MeasurementThe amount of camber change during a 10° steer to the left & rightspindle arc
23Tire wear factor of Caster Tires may show wear on both outer edges due to camber roll.Camber roll - the change in camber during a turn due to casterThe amount of camber change is relative to the amount of positive caster
24Camber Roll Left spindle down - right spindle up Left spindle up - right spindle down
25Caster may cause a PullCross caster is the side-to-side difference in caster measurementsMore than 1/2º difference side-to side may cause the vehicle to pull to the wheel with the least positive caster.
26Cross Caster Vehicle may pull to side of least positive caster Cross Caster = Left caster minus right caster2º caster1º casterVehicle may pull to side of least positive caster
27Caster Specification Preferred Spec Front 3.80º Rear n/a Tolerance Front 1ºCross caster .85º
30Front Toe Angles Incorrect front toe angles may cause: outside shoulder wearinside shoulder wearwanderingdartingTotal toe changes as the speed of the vehicle increases
31Total ToeThe difference in the distance measured between lines drawn through the center of tires on the same axle.Measurements are taken at the front and rear of the tires.
32Zero Total Toe80”Equal distance when measured across the front and the rear of tires on the same axle.
33Toe-In Measured distance is shorter between the front of the tires. front = 79 in.rear = 80 in.79”80”Total toe-in = 1 in.
34Excessive Toe-In Tire Wear OutsideshoulderwearCenterof car
35Toe-Out Measured distance is shorter between the front of the tires. front = 80 in.rear = 79 in.80”79”Total toe-out = 1 in.
36Excessive Toe-Out Tire Wear InsideshoulderwearCenterof car
37Total Toe AngleThe Total toe may also be displayed as an angle and expressed in degrees.Totaltoe angle
38Total Toe Specification Negative number indicates Toe-OutPositive number indicates Toe-In
39Individual ToeFront individual toe is responsible for steering wheel position
40Front Individual ToeLeft FrontIndividualtoe angleCenterlinetoeangleAngle formed by the intersection of the geometric centerline and a line drawn through the center of the wheel
41Rear Individual Toe Rear individual toe is responsible for: tire wear thrust anglevehicle tracking
42Rear Tire Wear Patterns Toe-InOutside shoulderToe-OutInside shoulderDiagonal Wipea condition that may result on rear tires with excessive toeDiagonal Wipe
43Geometric CenterlineA line drawn between the midpoint of both the front and rear axles.
44Thrust LineThe bisector of rear total toe. Also described as the direction the rear wheels are pushing the vehicle.
45Thrust Angle - formed by the intersection of the geometric centerline and the thrustline ( a line bisecting rear total toe )ThrustlineThrust angleGeometric Centerline
46Positive & Negative Thrust Angle +Positive Thrust Angle is to the RightNegative Thrust Angle is to the Left-
47Dog TrackingA visible dog track condition will be present, if the thrust angle is excessive.
48Review Front total toe is responsible for tire wear factors: excessive toe-in =outside shoulder weardartingexcessive toe-out =inside shoulder wearwanderingFront individual toe is responsible for steering wheel position
49Thrustline: the direction the rear wheels are pointing the vehicle bisector of the total toe angleThrust Angle: the angle formed by the intersection of the geometric centerline and the thrustlineRear tire wear patterns:outside or inside shoulder weardiagonal wipe if the toe angle is extremeMain Menu