Pre-Alignment Checks: Description: Caster

Caster is the tilting of front steering axis. This forward or backward tilt from vertical is viewed from side of vehicle. When axis is tilted backward from vertical, caster is said to be positive, creating a trailing action on front wheels. When axis is tilted forward, caster is negative, causing a leading action on front wheels.

Fig 1: Caster Angle Caster is amount of tilt forward or backward from vertical.