TORSION BAR SUSPENSION
What: There are no coil springs in a torsion bar suspension system. Instead, a torsion bar supports the vehicle weight and absorbs the road shocks. While a coil spring performs these functions by compressing, the torsion bar acts by twisting.
How: The torsion bar is connected between the lower control arm and the frame. The bar can be connected either longitudinally or transversely. Torsion bars can be used to adjust vehicle riding height. Not a way to lower the vehicle however, since ideally the lower control arm should be relatively parallel with the road surface when the vehicle is at rest. They are not interchangeable from side to side, because the direction of the twisting (or torsion) is different between the left and right sides.
Other than the difference between the torsion bar and the coil spring, this type of suspension is the same as the coil spring variety. Because the torsion bar is connected to the lower control arm, the lower ball joint is the load carrier. A shock absorber is connected between the lower control arm and the frame to dampen the twisting motion of the torsion bar.