What is a rear thrust angle?

The thrust angle is an imaginary line drawn perpendicular from the centerline of the rear axle down the centerline of the vehicle. The purpose of the thrust angle is to determine if the rear axle is lined up with the center of the vehicle and the front axle. The thrust angle also determines if the wheelbase on both sides of the vehicle is the same.

A thrust angle alignment attends to the procedure covered in a front-end alignment, but it also ensures that all four wheels are squared. A thrust angle alignment is recommended for vehicles that have independent rear suspensions. 

Suppose any wheels have an incorrect toe or your vehicle handles differently when turning in one direction versus the other. In that case, a thrust angle alignment will likely solve the problem. This alignment yields a better result in tire wear, fuel economy, and safety.