What is "positive caster" in vehicle suspension?

Positive caster refers to the angle created by the steering axis relative to the vertical line when viewed from the side of the vehicle. When discussing positive caster, this angle is tilted backward at the top in relation to the vertical plane, effectively meaning that the top of the steering axis leans toward the rear of the vehicle.

This tilted positioning has several important effects on vehicle handling and stability. With positive caster, when the driver steers the vehicle, the wheels naturally return to a straight position after the turn due to the self-centering action. This is largely because the contact patch of the tire moves behind the axis, which helps improve directional stability and reduces steering effort while providing better control at higher speeds.

Understanding the significance of positive caster is essential in suspension design and tuning, as it directly influences the feel and responsiveness of the steering system. It plays a crucial role in maintaining the vehicle’s stability during turns and contributing to the overall driving experience.