What does positive setback refer to?

Positive setback is a term used to describe a condition where the right side of a vehicle's axle is positioned closer to the front than the left side. In the context of the options provided, this means that the right side of the vehicle has a shorter wheelbase compared to the left side.

When assessing the vehicle's geometry, having a shorter wheelbase on one side can lead to handling issues and uneven tire wear, affecting the overall stability and performance of the vehicle. Thus, understanding positive setback helps technicians diagnose and adjust the alignment and suspension components properly to ensure even tire contact with the road, good handling characteristics, and overall vehicle safety.

The other options do not accurately define positive setback. The mention of tire positions or differences in wheelbase without proper context fails to convey the specific alignment conditions that positive setback encapsulates.