What is Torsion Bar Suspension?
Torsion bar suspension uses a torsion bar as its main weight-bearing spring — 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.
Vertical motion of the wheel causes the bar to twist around its axis and is resisted by the bar’s torsion resistance. The effective spring rate of the bar is determined by its length, cross section, and shape.
You can change the torsion bar or key to adjust the ride height, usually to compensate for engine weight.
While the ride height may be adjusted by turning the adjuster bolts on the stock torsion key, rotating the stock key too far can bend the adjusting bolt and place the shock piston outside its standard travel. Over-rotating the torsion bars can also cause the suspension to hit the bump-stop prematurely, causing a harsh ride.
How Torsion Bars Work Demonstrated and How To Adjust Ride Height
Dylan McCool demonstrates how torsion bars work on his 1969 Dodge Charger, as well as how to adjust your vehicle ride height with torsion bars…