Abstract: A vehicle trailer assembly is disclosed having a roll back frame for transport of a vehicle. A squat mechanism allows the roll back frame to define a smaller approach angle than normal with respect to the ground when in a loading position. The squat mechanism is self-actuated by movement of the roll back frame to the loading position and is self-releasing by return of the roll back frame to a transport position. The squat mechanism consists of a two bar mechanical linkage that compresses a spring which supports a main frame. By compressing the spring, the main frame is vertically lowered and the roll back frame, which pivots with respect to the main frame moves downwardly through a lesser distance. This lessens the approach angle to the roll back frame.