Torsion bar suspension

A torsion spring, also called torsion or only the torsion bar, a rod with a fixed clamping at both ends, wherein the fixed parts against each other can perform a pivotal movement about the axis of rotation. The torsion spring is used mainly in the automotive industry as a spring element.

To avoid undesirable bending of the spring, a support bearing is mounted on the rotary side. The maximum angle of rotation is dependent on the length and diameter of the torsion bar and the strength of the spring steel. Longer torsion bars allow for the larger rotation angle longer suspension stroke on the lever of the rotary side. Under load, the rod rotated about its longitudinal axis. The known particularly from the automotive torsion springs are usually made of solid round bars or packages of flat strips made of spring steel, the same length give way more than solid rods.

Torsion bars are used in landing gear in motor vehicle primarily as stabilizers or as resilient elements of the suspension. At the rear, the torsion bar suspension allows a broad trunk with a flat floor, as no strut towers protrude into the vehicle interior. Mostly they are used as a valve spring for piston engines - such as the motorcycle model Honda CB 450 K-series ( 1965-1976 ).


Known vehicles with torsion bar suspension - mostly the torsion bars are arranged transversely to the direction of travel - are the BMW 501/502, VW Beetle, VW Bus T1 and T2 VW Type 82 ( Kubelwagen ), Porsche 356, Porsche 911 ( to 1989) and Barkas; Torsion bar suspension can also be found on the rear axles of many car models of Peugeot and Renault - Renault 4, 5, 6 and 16 with slightly different wheelbase for the left and right side of the vehicle because the two parallel torsion bars across protrude above the center of the vehicle. In some torsion bar axles, such as the Porsche 356 and the BMW 501/502, the bias and thus the ground clearance of the vehicle can be adjusted by adjusting elements of the firmly clamped side of the spring.

Special way of U.S. automakers

Packard used 1955-1956 called for most models a torsion - Level Ride composite system, which essentially consists of two main longitudinal torsion bars and two auxiliary rods, which acted on the rear axle. With an intermediate, relay-controlled electric motor, the system worked as automatic level control: It stopped the car always horizontal and resembled within 7 seconds, the load in the trunk itself off. In addition, it could support a wheel change. The delay was necessary so that the electrics did not interfere with any unevenness in the ground, but only when a permanent change in weight occurred, for example, when passengers on or disembarked or the trunk was loaded.

Chrysler had 1957-1970 torsion -Aire called torsion bar suspension for the front axle. You should also reduce the excessive body roll when cornering. For the mounting of the rear axle has been long detained on leaf springs. The system was developed in 1971 to the Twist Quiet (until 1992 ).

General Motors went with his 1966 respectively. 1967 Oldsmobile Toronado introduced luxury coupe and Cadillac Eldorado ( until 1978 ) a similar path, but rather for reasons of space. Rear coil springs were always used.


The Czech Tatra 813 Tatra 815 and up to four-axle all-terrain utility vehicles with extremely central tube frame and individually suspended on half axles wheels. The 4x4 variants are on all axles and 6x6 variants are sprung on the rear axles with longitudinally installed torsion bars. The front axle of 6x6 and 8x8 all axes of variation are suspended on semi-elliptic leaf springs. The Tractor variant is equipped at the front axle with torsion bar suspension and at the rear axles with air springs.

Another field of application for torsion bars are battle tanks: Since the Second World War, the suspension of medium based ( PzKw III - from Ausf E, Panthers ) and heavy tanks (Tiger and King Tiger) as well as in modern battle tanks such as the Leopard 2 on torsion bars.


In rail vehicles torsion bar springs are used as rolling support; they spring from the roll motion of the vehicle body about the longitudinal axis. Especially for vehicles with air suspension anti-roll devices are a crucial part of the suspension. The torsion bar of the Anti-roll may be installed depending on the space in the chassis or vehicle frame.