Torsion Bar Suspension - History

History

Before World War II, the front wheel drive Citroen Traction Avant (1934) had independent front torsion bar suspension and a flexible trailing dead axle, also sprung by torsion bars. The flexibility of the axle beam provided wheel location features like a twist beam axle. The Czechoslovakian Tatra cars designed by Professor Hans Ledwinka in the mid-1930s used all round independent torsion bar suspension, along with air cooled rear engines. Also in the 1930s, prototypes of the first Volkswagen Beetle incorporated torsion bars—especially its transverse mounting style. Ledwinka's concept had been copied by Ferdinand Porsche, whose successors later had to acknowledge the influence of Ledwinka's sophisticated Tatra models on the Porsche-designed Kdf-Wagen of 1938 (later renamed the VW Beetle), a post-war lawsuit resulting in a DM3,000,000 settlement paid by Volkswagen to Ringhoffer-Tatra in 1961.

The system was applied to many new combat vehicle designs during the Second World War. It was used extensively in European cars Renault, Citroën and Volkswagen, as well as by Packard in the 1950s. The Packard used torsion bars at both front and rear, and interconnected the front and rear systems to improve ride quality. The then revolutionary Jaguar E-Type introduced in 1961 had a unique torsion bar front suspension and an independent coil spring rear suspension using four shock absorbers with concentric springs.

An early application of a torsion bar in an American car was by Hudson Motor Car Company of Detroit who had introduced the innovative front Axle Flex suspension in 1934 Hudson and Terraplane cars and realized for 1935 that a transverse torsion bar linked to the rear axle was needed as an anti-roll bar to stabilize the cars. The single torsion bar was mounted through the frame sides behind the rear axle and then attached by arms and links to the front side of the spring U-bolt plates. Axle Flex was discontinued for the 1936 model year.

The most famous American passenger car application was the Chrysler system used beginning with the 1957 model year, although Chrysler's "Torsion-Aire" suspension was only for the front; the same basic system (longitudinal mounting) was maintained until the 1981 introduction of the K-car. A reengineered torsion bar suspension, introduced with the 1976 Dodge Aspen, introduced transverse-mounted torsion bars (possibly based on the Volkswagen Type 3 passenger car) until production ended in 1989 (with Chrysler's M platform). Light duty Dodge trucks however continue to use torsion bars on their front suspension.

General Motors has used torsion bars since 1966, starting with the E-platform vehicles (Oldsmobile Toronado, Cadillac Eldorado), 4 wheel drive S-10 pickups & Astro vans, and since 1988, full size trucks (GMT400, GMT800, and GMT900 series).

Porsche used torsion bar suspension for their 911 series from 1963 until 1989 with the introduction of the 964. They are also used in the rear suspension of the 924, 944, and 968.