Presentation on theme: "Automotive Alignment Angles"— Presentation transcript:
1 Automotive Alignment Angles CamberCasterFront toeRear toe
2 Primary Alignment Angles Front CamberRear CamberCasterFront ToeRear Toe2 lines meetto form anAngle
3 0 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
4 Zero Camber Wheel is vertical when viewed from the front Measured as Zero degreesApplicable to front and rear tires
5 Reasons to use at or near Zero Camber Extremely wide tiresPositive offset rimsExtended Tire life
6 Positive CamberTop of tire leans outboard at the top when viewed from the frontMeasured in degreesPrimarily used on front wheels
7 Reasons to use Positive Camber Places load inboard on spindleIncreases road isolationIncreases directional stability
8 Negative CamberTop of tire leans inboard at the top when viewed from the frontMeasured in degreesPrimarily used on rear wheels
9 Reasons to use Negative Camber Places load outboard on spindleIncreased cornering abilityIncreases road shock & component wear
10 Outside Shoulder Wear due to Excessive Positive Camber Angle
11 Camber 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.
12 Excessive Cross Camber Vehicle may pull to side of most positive camber
13 Camber Specifications Preferred Specs Front = 0º Rear = -.40ºTolerance Front = 1º Rear = .75ºCross camber .70º
15 CasterFrontThe Forward or Rearward Tilt of the Steering Axis as viewed from the sideTypical RangeTypical tolerance ± 1º1º to 6 º positive
16 Steering Axis Line drawn between the two pivot points of the steering knuckle
17 Zero CasterSteering Axis is vertical as viewed from the side and measured as 0º
18 Negative CasterForward tilt of the Steering Axis as viewed from the side and measured in degreesFront
19 Positive CasterRearward tilt of the Steering Axis as viewed from the side and measured in degreesFront
20 Benefits 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 ….
21 Negative 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
22 Caster MeasurementThe amount of camber change during a 10° steer to the left & rightspindle arc
23 Tire 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
24 Camber Roll Left spindle down - right spindle up Left spindle up - right spindle down
25 Caster 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.
26 Cross 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
27 Caster Specification Preferred Spec Front 3.80º Rear n/a Tolerance Front 1ºCross caster .85º
30 Front Toe Angles Incorrect front toe angles may cause: outside shoulder wearinside shoulder wearwanderingdartingTotal toe changes as the speed of the vehicle increases
31 Total 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.
32 Zero Total Toe80”Equal distance when measured across the front and the rear of tires on the same axle.
33 Toe-In Measured distance is shorter between the front of the tires. front = 79 in.rear = 80 in.79”80”Total toe-in = 1 in.
34 Excessive Toe-In Tire Wear OutsideshoulderwearCenterof car
35 Toe-Out Measured distance is shorter between the front of the tires. front = 80 in.rear = 79 in.80”79”Total toe-out = 1 in.
36 Excessive Toe-Out Tire Wear InsideshoulderwearCenterof car
37 Total Toe AngleThe Total toe may also be displayed as an angle and expressed in degrees.Totaltoe angle
38 Total Toe Specification Negative number indicates Toe-OutPositive number indicates Toe-In
39 Individual ToeFront individual toe is responsible for steering wheel position
40 Front Individual ToeLeft FrontIndividualtoe angleCenterlinetoeangleAngle formed by the intersection of the geometric centerline and a line drawn through the center of the wheel
41 Rear Individual Toe Rear individual toe is responsible for: tire wear thrust anglevehicle tracking
42 Rear Tire Wear Patterns Toe-InOutside shoulderToe-OutInside shoulderDiagonal Wipea condition that may result on rear tires with excessive toeDiagonal Wipe
43 Geometric CenterlineA line drawn between the midpoint of both the front and rear axles.
44 Thrust LineThe bisector of rear total toe. Also described as the direction the rear wheels are pushing the vehicle.
45 Thrust Angle - formed by the intersection of the geometric centerline and the thrustline ( a line bisecting rear total toe )ThrustlineThrust angleGeometric Centerline
46 Positive & Negative Thrust Angle +Positive Thrust Angle is to the RightNegative Thrust Angle is to the Left-
47 Dog TrackingA visible dog track condition will be present, if the thrust angle is excessive.
48 Review 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
49 Thrustline: 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