A torsion bar suspension, also known as a torsion spring suspension, is any vehicle suspension that uses a torsion bar as its main weight-bearing spring. Torsion Bar Suspension The torsion bar is basically a length of metal rod anchored at one end to the car body and at the other end to the suspension lower link. As the wheel passes over a bump the bar twists. One end of a long metal bar is attached firmly to the vehicle chassis; the opposite end terminates in a lever, the torsion key, mounted perpendicular to the bar, that is attached to a suspension arm, a spindle, or the axle. The torsion bar suspension has become popular in Chevy's 4WD truck line, in which the switch to independent front suspension (IFS) leaves little room for a standard coil spring. The average backyard mechanic can adjust the torsion bars on a Chevrolet in about 20 minutes. It returns to its original position when the bump is passed and restores the car to …