Torsion Bar
A type of suspension spring consisting of a steel rod that twists under load to absorb road shocks.
A torsion bar is a type of suspension spring consisting of a long, straight rod of spring steel. One end of the torsion bar is anchored rigidly to the vehicle's frame or crossmember, while the other end is connected to the lower control arm of the wheel suspension. As the wheel moves up and down over bumps, the control arm twists the steel rod along its length, which resists the twisting motion to absorb road shocks.
Torsion bars are commonly used on trucks, SUVs, and classic cars because they are compact and extremely durable. They take up less space than coil springs, allowing for more clearance around drive axles. Additionally, torsion bar suspensions feature an adjustment key or bolt at the frame mount, allowing mechanics to easily adjust the vehicle's ride height or level the front suspension after installing heavy accessories.
Symptoms of torsion bar system issues include a sagging ride height on one side, harsh ride quality, and squeaking noises from the mounting bushings. Over time, the torsion bar adjustments can settle, requiring a suspension adjustment. If a torsion bar cracks or breaks, the suspension will collapse completely onto the bump stops, requiring immediate bar replacement.