Caster angle is the inclination of the king pin toward the front or rear of the vehicle. Caster helps keep the wheels in a straight-ahead position and assists the driver in returning to a straight-ahead position after a turn.

Positive caster is the tilting of the king pin toward the rear of the vehicle.

Negative cater is the tilting of the king pin toward the front of the vehicle.

Caster does not affect tire wear.