Toyota RAV4 > Suspension and steering > Wheel alignment — general information

Wheel alignment — general information

1. A wheel alignment refers to the adjustments made to the wheels so they are in proper angular relationship to the suspension and the ground. Wheels that are out of proper alignment not only affect vehicle control, but also increase tire wear. The front-end angles normally measured are camber, caster and toe-in (see illustration). Toe-in and camber are adjustable; if the caster is not correct, check for bent components. Rear camber and toe-in are also adjustable.

i. 1 Camber, caster and toe-in angles

А minus B = C (degrees camber)
D = degrees caster
E minus F = toe-in (measured in inches) G = toe-in (expressed in degrees)
G = toe-in (expressed in degrees)

2. Getting the proper wheel alignment is a very exacting process, one in which complicated and expensive machines are necessary to perform the job properly. Because of this, you should have a technician with the proper equipment perform these tasks.

3. Toe-in is the turning in of the wheels. The purpose of a toe specification is to ensure parallel rolling of the wheels. In a vehicle with zero toe-in, the distance between the front edges of the wheels will be the same as the distance between the rear edges of the wheels. The actual amount of toe-in is normally only a fraction of an inch. Incorrect toe-in will cause the tires to wear improperly by making them scrub against the road surface.

4. Camber is the tilting of the wheels from vertical when viewed from one end of the vehicle. When the wheels tilt out at the top, the camber is said to be positive (+). When the wheels tilt in at the top the camber is negative (-). The amount of tilt is measured in degrees from vertical and this measurement is called the camber angle. This angle affects the amount of tire tread which contacts the road and compensates for changes in the suspension geometry when the vehicle is cornering or traveling over an undulating surface.

5. Caster is the tilting of the front steering axis from vertical. A tilt toward the rear is positive caster and a tilt toward the front is negative caster.

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