Alignment: Description and Operation
DESCRIPTIONVehicle wheel alignment is the proper adjustment of all interrelated front and rear suspension angles. These angles are what affects the handling and steering of the vehicle when it is in motion.
The method of checking a vehicle's front and rear wheel alignment will vary depending on the type and manufacturer of the equipment being used. Instructions furnished by the manufacturer of the equipment being used should always be followed to ensure accuracy of the alignment, except when alignment specifications recommended by Daimler/Chrysler Corporation differ.
Typical wheel alignment angles and measurements are camber, caster, toe, and thrust angle.
- Camber is the number of degrees the top of the tire and wheel assembly is tilted either inward or outward. Camber is a tire wearing angle. Excessive negative camber will cause tread wear at the inside of the tire, while excessive positive camber will cause outside tire wear.
- Cross Camber is the difference between left and right camber. To achieve the cross camber reading, subtract the right side camber reading from the left. For example, if the left camber is +0.31| and the right camber is 0.01|, the cross camber would be +0.31|.
- Caster is the number of degrees of forward or rearward tilt of the steering knuckle. Forward tilt provides a negative caster angle, while rearward tilt provides a positive caster angle. Although caster does not affect tire wear, a caster imbalance (side-to-side) on the vehicle may cause the vehicle to lead to the side with the least positive caster. Caster is not adjustable on this vehicle.
- Cross Caster is the difference between left and right caster.
- Toe is measured in degrees or inches and is the difference in width between the centered leading and trailing edges of the tires on the same axle. Toe-in means that the front width is more narrow than the rear. Toe-out means that the front width is wider than the rear.
- Thrust Angle is defined as the average of the toe settings on each rear wheel. If this measurement is out of specification, readjust the rear wheel toe so that each wheel has 1/2 of the total toe measurement. When readjusting, do not exceed the total toe specification.
Wheel alignment on this vehicle is to be checked and all alignment adjustments are to be made with the vehicle standing at its curb height specification. Curb height is the riding height of the vehicle measured from a certain point on the vehicle to the ground while the vehicle is setting on a flat, level surface.