What affects the caster angle in a vehicle's suspension system?

The caster angle in a vehicle's suspension system is directly affected by the angle between the steering axis and the vertical axis. This angle is crucial for vehicle stability, particularly in straight-line driving and when cornering. A positive caster angle means that the steering axis is tilted towards the driver, helping to ensure that the wheels return to a straight position after turning. This characteristic gives a vehicle better control and handling.

When the steering axis is aligned vertically or has a negative caster angle, it can lead to poor steering response and increased effort needed to steer, which negatively affects handling. Thus, understanding the relationship between the steering axis and verticality is essential for proper alignment and vehicle dynamics.

While other factors such as tire pressure, wheel alignment, and type of suspension can influence the overall performance and feel of the vehicle, they do not define the caster angle itself in the same direct manner as the angle between the steering axis and the vertical axis does.