Torsion bar

A long spring steel rod attached in such a way that one end is anchored while the other is free to twist. One end is fastened to the frame at one end and to a suspension part at the other. If an arm is attached, at right angles, to the free end, any movement of the arm will cause the rod or bar to twist the bar's resistance to twisting provides a spring action. The torsion bar replaces both coilleaf springs in some suspension systems. The main advantage of the torsion bar over the coil spring in the front suspension is the ease of adjusting front suspension height.