Vehicle Alignment, Suspension and Undercar Service
Aligning a car or truck involves the adjustment of the vehicle's suspension, not the tires and wheels. The direction and the angles that the tires point in after the alignment is complete, however, are critically important. There are four factors involved in setting the alignment to specification: caster, camber, toe and ride height. The following brief discussion of each aspect will help you understand the process and spot potential problems
Alignment is one of the key maintenance factors in getting the most wear and performance from your tires. In addition, wheel alignment provides safe, predictable vehicle control as well as a smooth and comfortable ride that's free of pulling or vibration. Today's modern suspensions require a precise four-wheel alignment that can only be achieved through a modern alignment system. This applies to both front and rear wheel drive vehicles.
Caster is the angle of the steering axis (the part of the suspension that supports the wheel and tire assembly). Viewed from the side of the vehicle, an imaginary line drawn between the centers of the upper and lower ball joints forms an angle with true vertical; this is defined as caster. The illustration to the right shows whether this angle is referred to as positive or negative. Caster is important to steering feel and high-speed stability
Viewed from the front of the vehicle, camber describes the inward or outward tilt of the tire. The illustration to the right shows whether this tilt is referred to as positive or negative. The camber adjustment maximizes the tire-to-road contact and takes into account the changes of force when a vehicle is turning. Camber is the one adjustment that can be set according to driving habits. Generally, if you drive more aggressively when cornering, more negative camber can be set. If you drive on highways and do very little hard cornering, more positive camber can be set.