Caster

Caster is the amount that the top of the strut is tilted forward or rearward from the vertical. When the strut tilts rearward, the caster is "positive" (+). The amount of tilt is measured in degrees from the vertical.

Caster influences directional control of the steering, but does not affect tire wear. Weak springs or overloads will affect caster.

If one wheel has more positive caster than the other, it will cause the wheel to pull toward the center of the vehicle. This will cause the vehicle to move or lead toward the side with the least positive caster.