Citroën: death of the hydropneumatic suspension
The last ever hydropneumatic suspension equipped car form Citroën, a C5, came out of the production line last week in Rennes, France. The French carmaker kills its revolutional suspension system that changed the world in 1955 and helped to put Citroën into the history books.
Presented at the 1955 Paris Motor Show on the first ever DS, the hydropneumatic suspension was based on the “oléopneumatique” system invented by George Messier in 1925. Even if evolution was constant every time Citroen presented a new car, the basic principal stayed the same: a high-pressure pump driven by the engine or an electric motor depending on the car type, coupled to an accumulator that distributes oil in the hydraulic circuit. The force generated by it was used to assist the steering, the brakes and the transmission. In small green globes, it was used in combination with nitrogen for the suspension.
Hard to maintain
“It was a prodigious progress, giving never-seen-before road sensations and a colossal advantage. Compared to convectional cars, it corrected body movements and kept the wheel in constant contact with the road”, explains Philippe Casse, automobile historian.
All of Citroën’s big cars were equipped with this suspension and even some more mainstream ones like the BX or Xantia. Lately, the C6 was the last car equipped as standard with the hydropneumatic suspension. It was only available as a costly option on the C5.
Today, the system is seen as too complex, to expensive and to difficult to maintain even if no one rejects its effectiveness. Progress in terms of suspension with electronic, mechanic or magnetic systems rendered the hydropneumatic obsolete. It will forever stay in museum and history books as one of the best innovations in the world of cars.