Torsion bar suspension

The effective spring rate of the bar is determined by its length, cross section, shape, material, and manufacturing process.

Torsion bar suspensions are used on combat vehicles and tanks like the T-72, Leopard 1, Leopard 2, M26 Pershing, M18 Hellcat, M48 Patton, M60 Patton and the M1 Abrams (many tanks from World War II used this suspension), and on modern trucks and SUVs from Ford, Chrysler, GM, Mitsubishi, Mazda, Nissan, Isuzu, LuAZ, and Toyota.

Manufacturers change the torsion bar or key to adjust the ride height, usually to compensate for engine weight.

Torsion bars reached the height of their popularity on mass-production road cars in the middle of the 20th century at the same time that unitary construction was being adopted.

Using MacPherson struts to achieve independent front suspension with coil springs meant providing strong turrets in the frontal structure of the car.

Morris Minor and Oxford from the late 1940s onwards used a front torsion bar system very similar to the Citroën, as did the Riley RM models.

Gladeon M. Barnes and Warren E. Preston filed a US patent application for a torsion bar suspension in 1934, which was approved two years later.

Even though Barnes was employed by the US Army Ordnance Department, torsion bars were not used in American armor designs until the T70 GMC in 1943, which suspension was derived from Pz.

The Oxford/Six platform was developed through several revised series which used Issigonis' torsion bar system until 1959 when the new Farina Oxford was introduced using front suspension with coil springs, lower wishbones and lever arm dampers.

Its first use in a passenger car was in 1966, starting with the E-platform vehicles (Oldsmobile Toronado, Cadillac Eldorado), 4WD S-10 pickups and Astro vans with optional AWD, and since 1988, full size trucks and SUVs with 4WD (GMT400, GMT800, and GMT900 series).

[citation needed] Due to their small size, tremendous load capacity, and relative ease of service, torsion bar suspension has been ideal for tanks, though it is not without disadvantage.

The large travel and high elasticity of the torsion bars results in a "rocking" motion when the tank is moving or coming to a sudden stop.

Due to the massive weight of a main battle tank, compared to an automobile, there is a much greater risk of breaking a torsion bar on sudden bumps or maneuvers, and if it is not replaced in short order the reduced suspension can affect the maneuverability of the vehicle, and in extreme cases risk immobilizing the vehicle as the reduced capacity of the suspension causes additional torsion bars to break.