What best describes positive caster?

Positive caster is best described as the rearward tilt of the steering axis. This tilt is crucial for vehicle stability and handling. When the steering axis has a positive caster angle, it means that the top of the steering axis is tilted toward the rear of the vehicle when viewed from the side. This configuration helps the front wheels to maintain better contact with the road during cornering and supports self-centering of the steering wheel, which enhances driver control and overall stability of the vehicle.

Positive caster also influences the steering feel, providing resistance to steering effort when the vehicle is at speed, which contributes to a more stable ride. Additionally, it helps to improve the vehicle's response to steering inputs, particularly during turns, as the weight transfer during cornering helps press the tires into the road more effectively.

In contrast, the other options do not accurately describe positive caster. The forward tilt of the steering axis would indicate negative caster, while tilting the tire inward or outward does not define the steering axis' position concerning the vertical line needed to determine caster angle.