Which alignment angle is usually considered the greatest tire wearing angle?

The angle that is typically considered the greatest tire wearing angle is toe. Toe refers to the angle at which the tires point relative to the centerline of the vehicle when viewed from above. When there is improper toe alignment, it can lead to excessive tire wear, primarily because the tires are either angled inward (toe-in) or outward (toe-out) as the vehicle is driven. This misalignment causes the tires to scrub against the road, resulting in uneven wear patterns that can drastically reduce tire life.

Camber and caster are also alignment angles that affect handling and tire wear but are generally not associated with as significant or immediate an impact on tire wear as toe. Camber impacts tire wear across the tire's width, while caster influences the steering and stability of the vehicle. SAI (Steering Axis Inclination) and KPI (King Pin Inclination) primarily affect the steering characteristics and stability but do not directly contribute to tire wear the way toe does. Thus, ensuring proper toe alignment is critical for optimal tire performance and longevity.