A new type of smooth car suspension

WHEN unveiled at the Paris Motor Show in 1955, the Citroën DS caused a sensation. It was not just the car's elegant lines that encouraged 12,000 customers to place immediate orders, but also its mechanical innovations. Chief among these was that instead of steel springs, the DS rode on a self-levelling hydropneumatic suspension. This used spheres, filled with nitrogen, connected to each wheel. When started, the car's engine pumped hydraulic fluid into the spheres, lifting the vehicle's body. Bu...