Caster angle describes the inclination of the steering axis from the vertical when viewed from the vehicle's side.
A positive caster angle enhances straight-line stability at the cost of increased steering effort.
Excessive positive caster not only raises steering effort further but also transmits more road shock to the steering wheel.
Consequently, the driver experiences bumps and vibrations more intensely via the steering.
While the front wheel's suspension absorbs shocks, the steering system relays these to the driver's hands.
In this scenario, the passenger seat and rear axle are not directly influenced by the caster angle.
Therefore, the relevant component is steering.