Section 339 (Wheel Alignment Specifications & Adjustment Procedures): Description: Caster
WARNING: This page is about a different car, the 2004 Chrysler Pacifica. However, it is still accessible from the selected car via links, so may be relevant.
Caster is forward or rearward tilt of steering knuckle in reference to position of upper and lower ball joints. Caster is measured in degrees of angle relative to a true vertical center line. This line is viewed from side of tire and wheel assembly. See Fig 1 .
- Forward tilt (upper ball joint ahead of lower) results in a negative caster angle.
- Rearward tilt (upper ball joint trailing lower) results in a positive caster angle.
Although caster does not affect tire wear, a caster imbalance between 2 front wheels may cause vehicle to lead to side with least positive caster.