What does "caster" refer to in suspension terms?

Caster refers to the angle of the steering axis when viewed from the side of the vehicle. This angle significantly influences the steering characteristics and handling of a vehicle. When the steering axis is inclined rearward at the top, it results in positive caster, which enhances the vehicle's straight-line stability and self-centering of the steering wheel. This means that as the vehicle moves forward, the wheels are naturally biased to return to the center position after a turn, improving control and driver comfort.

Understanding caster is important for vehicle alignment and performance tuning. Adjustments to this angle can bring about changes in how the vehicle behaves, particularly in response to steering inputs during cornering or driving on uneven surfaces.

The other options do not correctly define caster. The distance between the front and rear axles relates to wheelbase, while tire type and weight distribution are not directly linked to the caster angle, which is strictly about the steering axis' orientation.