What Are Camber-Caster Plates?

In this article we'll be discussing what camber-caster plates do for your car's suspension system. 

Caster has a direct relationship with camber and when possible, coilover manufacturers integrate camber and caster adjustability into a single upper mount. Caster, or caster angle is the top-to-bottom angle of the steering axis and suspension components as they meet the wheel. Caster angle is observed from a side-view of the vehicle. Camber, or camber angle is the angle of the wheels relative to the ground, assuming the ground is perfectly flat and is observed from a front view of the vehicle. 

Camber-caster plates are only compatible for use on vehicles that utilize McPherson front struts (and sometimes rear). Vehicles that utilize double wishbone suspension, also known as double A-arm suspension are incompatible with camber-caster plates. The information contained in this article applies to McPherson Strut suspension systems only. 

Caster angle is adjusted to optimize vehicle handling characteristics while driving on diverse tracks and road surfaces or to accommodate distinctive driving styles. Positive caster is common for track vehicles and has a direct relationship with camber, allowing the tire to “lean” into turns and provide “self-centering” effects on the wheels when exiting corners, both of which improve handling of the vehicle at high and low speeds. When the tire leans into the turn, negative camber of the outside front wheel increases which in turn, increases the contact patch between the tire and racetrack. 

Positive, negative, or neutral caster is easily observed in a side view of the front wheels looking at the strut. The angle of the strut relative to the center of the wheel results in negative, positive, or neutral caster. For this example, the front left (driver’s side) is used. If the strut’s upright mounting points are perfectly vertical in relation to the center of the wheel, neutral or zero caster is achieved. Positive caster can be achieved by positioning the strut’s top mounting point rearward. Alternately, negative caster can be achieved by positioning the strut’s top mounting point frontward. 

Positive, negative, or neutral camber is easily observed in a front view of the front wheels. Both caster and camber are measured and expressed in degrees. When the wheel is perfectly perpendicular to the ground surface, its camber is zero degrees and neutral camber is achieved. If the top of the wheel leans outward from the centerline of the car positive camber is achieved. Alternately, if the top of the wheel leans inward from the centerline of the car negative camber is achieved.

Most coilover manufacturer camber-caster plates are engineered to allow for approximately -3 to +3 degrees of adjustability but depending on the vehicle and other suspension components, and camber-caster plate manufacturer, adjustment range can vary.