Proper adjustment affects safety, handling and economy. An important part of vehicle safety is directional control. Does the vehicle travel straight down a highway? Does it steer easily? Are the tires subject to excessive premature wear? Does the steering wheel return to the straight ahead position after turning a corner? For the answer to be YES to all these questions, the vehicle must be properly aligned.
Wheel alignment is the adjustment of caster, camber and toe in angles. The alignment of one of these angles affects the other two angles. On strut systems, there may or may not be provisions for the caster and camber adjustments. However, toe angles are adjustable on most systems. Toe settings are the most critical tire wearing angles. The purpose of toe is to ensure parallel rolling of the front and rear wheels, but if either wheel has too much toe-in or toeout, the tires will sideslip. This results in a featheredged scuff across the face of the tire which causes premature tire wear.