Alignments Keep Your Vehicle From Wandering, Aids In Proper Braking, Prevents Premature Tread Wear.

Adjustments For Keeping Your Vehicle Properly Aligned

Caster
Caster is the most difficult to understand. Caster is the forward or backward tilt of the kingpin or support arm at the top of a wheel-suspension assembly, and it is measured in degrees. Forward tilt is called negative caster, and backward is positive caster.

From tire-wear and fuel-economy standpoints, caster is the least critical element of alignment. But it has a profound impact on vehicle stability and handling.

Modern vehicles are designed to include some degree of positive caster. This causes the left front wheel to lift the vehicle slightly when the wheels are turned left, and the right front wheel to lift the vehicle during a right turn. Thus, gravity and the weight of the vehicle's front end try to keep the front wheels pointing straight ahead as the vehicle is going down the road.

While it doesn't usually cause abnormal tire wear, improper caster is frequently at the reason for driver complaints of wandering and pulling.