Caster

Caster is the forward or rearward tilt of a vehicle’s steering axis when viewed from the side. It is an alignment angle that affects straight-line stability, steering feel and return-to-centre behaviour.

Positive and negative caster

Positive caster means the upper steering pivot is behind the lower pivot when viewed from the side. Most modern vehicles use positive caster to improve stability and help the steering return toward centre after a turn. Negative caster is less common in normal road-vehicle applications.

Why caster matters

Unequal caster from side to side can contribute to a pull or different steering effort. Excessive changes may affect steering weight and suspension geometry. Caster itself does not usually cause the same direct tire-wear pattern as toe or camber, but the underlying damage or misalignment may affect overall handling.

When to check caster

Caster should be measured after impacts, suspension repairs, ride-height changes or when a vehicle does not track correctly. Some vehicles provide factory adjustment, while others require component inspection or specialized correction.

Related terms

Camber, toe alignment, steering response and wheel alignment.