A powered de Dion suspension uses universal joints on both ends of its driveshafts (at the wheel hubs and at the differential), and a solid tubular beam to hold the opposite wheels in parallel. Unlike an anti-roll bar, a de Dion tube is not directly connected to the chassis, and is not intended to flex. In suspension geometry it is a beam axle suspension.
Unlike most fully independent suspension there are no camber changes on axle loading and unloading (or rebound). Fixing the camber of both wheels at 0° assists in obtaining good traction from wide tires and also tends to reduce wheel hop under high power operations compared to an independent suspension.
The two wheels may be individually aligned, allowing for independent camber (vertical) and track (horizontal) alignment.
Disadvantages:
A pair of CV or universal joints is required for each wheel, adding complexity, cost, and weight.[2]
If coil springs are used, then a lateral location link (usually either a Panhard rod or Watt's linkage) is required, plus additional torque links on each side (five link suspension) or a combination of lower trailing links and an upper transverse wishbone. None of these additional links are required if leaf springs are used, but ride can be compromised due to the leaves having to do double duty as both locating links and springs. The torque links are not required if the setup uses inboard brakes, like in the Pegaso 1502, Rover P6, all Iso cars[6] and Alfa Romeo type 116 (and derivatives), as the wheels do not transmit torque to the suspension.
Sympathetic camber changes on opposite wheels are seen on single-wheel suspension compression, just as in a Hotchkiss drive or live axle. This is not important for operation on improved surfaces but is more critical for rough road or off-road use.
The Smart Fortwo (and Smart Roadster before) micro-compact cars produced by Daimler AG, Mitsubishi ikei car produced by Mitsubishi Motors and the Caterham 7 (a development of the Lotus Seven after Lotus sold the design rights to Caterham Cars), are the only cars recently in production that use this arrangement, as well as the products of some kit car companies. A recent vehicle to use this suspension coupled with leaf springs was the Ford Ranger EV. The American-built MV-1 van by VPG, produced from 2010 to 2016, also used this suspension in the rear with leaf springs.[7] 4WD variants of the Honda Fit and Honda HR-V subcompact SUV have been reported as using a de Dion style suspension;[8] however, these vehicles actually have a twist-beam rear suspension, with the cross beam element located even further forward (and thus even more like a trailing arm and less like the beam axle of a de Dion) than the 2WD variants. The Mitsubishi Fuso eCanter uses a DeDeion rear axle with leaf springs.
The 2024 Mercedes-Benz EQG (G580 EQ) also uses a De Dion type rear axle, with double universal joint driveshafts transferring drive propulsion from the electric motors and incorporating slip joints to equalize the length.[9]
Other notable uses
Most models of the Kawasaki MULE line of utility vehicles feature a leaf-sprung de Dion rear suspension with a distinctively curved tube axle that clears the rear subframe to provide 50mm (2 inches) of wheel travel.[10] Benefits include simplicity, durability, compactness and a relatively low liftover height for the cargo bed.
Walter Snow Fighter plow trucks produced by the Walter Truck Company of Long Island, New York throughout the mid 20th century used de Dion axles with portal gear hubs for both the front and the rear suspension, allowing the use of large differentials for durability without increasing unsprung weight or reducing ground clearance. Forged steel axles were used instead of tubes.
UC San Diego’s Formula SAE team, Triton Racing, has employed the use of de Dion rear suspension in their vehicles since 2015. They are one of the few teams in the competition to do so.[11]
Ferrari also used this type of suspension on its 1976 F1 model 312T6, which had the peculiarity of mounting four wheels at the rear, two on each side[12] and therefore only one axle.[13][14]
References
^Setright, L. J. K. "De Dion axle: The First Step to Independence", in Ward, Ian, executive editor. World of Automobiles (London: Orbis, 1974), Volume 5, p.500.
G.N. Georgano (1990). Cars: Early and Vintage, 1886-1930. London: Grange-Universal. (reprints AB Nordbok 1985 edition).
Setright, L. J. K. "De Dion axle: The First Step to Independence", in Ward, Ian, executive editor. World of Automobiles, Volume 5, pp. 515–516. London: Orbis, 1974.