See Figure 1
The procedure for checking and adjusting front wheel alignment requires specialized equipment and professional skills. The following descriptions and adjustment procedures are for general reference only.
Front wheel alignment is the position of the front wheels relative to each other and to the vehicle. It is determined, and must be maintained to provide safe, accurate steering with minimum tire wear. Many factors are involved in wheel alignment and adjustments are provided to return those that might change due to normal wear to their original value. The factors which determine wheel alignment are dependent on one another; therefore, when one of the factors is adjusted, the others must be adjusted to compensate.
Descriptions of these factors and their affects on the car are provided below.
The wheel alignment should not be adjusted without first making a thorough inspection of the front suspension components.
Camber angle is the number of degrees that the centerline of the wheel is inclined from the vertical. Camber reduces loading of the outer wheel bearing and improves the tire contact patch while cornering.
Caster angle is the number of degrees that a line drawn through the steering knuckle pivots is inclined from the vertical, toward the front or rear of the car (when viewed from the side of the car). Caster improves the directional stability and decreases susceptibility to crosswinds or road surface deviations.
Toe-in is the difference of the distance between the centers of the front and rear of the front wheels. It is most commonly measured in inches, but is occasionally referred to as an angle between the wheels. Toe-in is necessary to compensate for the tendency of the wheels to deflect rearward while in motion. Due to this tendency, the wheels of a vehicle, with properly adjusted toe-in, are traveling straight forward when the vehicle itself is traveling straight forward, resulting in directional stability and minimum tire wear.
Steering wheel spoke misalignment is often an indication of incorrect front end alignment. Care should be exercised when aligning the front end to maintain steering wheel spoke position. When adjusting the tie rod ends, adjust each an equal amount (in the opposite direction) to increase or decrease toe-in. If, following toe-in adjustment, further adjustments are necessary to center the steering wheel spokes, adjust the tie rod ends an equal amount in the same direction.