Launch a car today with hydropneumatic suspension, self-levelling, automatic jacking, a semi-automatic gearbox, low-drag aerodynamics and an innovative structure and it would look highly advanced. Citroën did just that with the DS, and they did it more than 50 years ago.
The first plans for the 'Voiture à Grande Diffusion' (mass-market car) were laid down in 1938 but work was interrupted by the war. Development did not restart until the late 1940s as the 2CV was considered a higher priority, but when work did resume Citroën chief designer André Lefebvre resolved to make the new car genuinely radical. From a company which had already pioneered monocoque construction and front-wheel drive with the Traction Avant of the 1930s, that meant the new car would be truly special.
Stylist Flaminio Bertoni produced a forward-looking teardrop shape with a low nose and integrated wings. In a bold break with convention there was no radiator grille, air for the engine being drawn in under the car. Because the low nose left little room for the engine, Citroën's Italian engine designer Walter Becchia proposed a compact air-cooled flat six to be mounted right at the front with the gearbox behind, driving the front wheels. But prototype engines were plagued with over-heating and misfiring, and the extreme forward location of the engine upset the weight distribution.
So the flat six was abandoned, replaced by an updated version of the 1911cc in-line four from the Traction Avant. Because the engine was much taller than the flat six it had to be mounted a long way back in the engine bay, so far back that it encroached on the cabin. As in the Traction Avant drive was taken forwards to a conventional gearbox, but in the new car that gearbox was operated hydraulically by a lever on top of the steering column.
Engineer Paul Magès was responsible for the hydraulic system, which did far more than just chage gears: it also powered the clutch and brakes, and provided advanced self-levelling suspension. The system used six steel spheres, each separated into two chambers by a rubber diaphragm with the fluid on one side and nitrogen gas on the other. The first sphere acted as a pressure accumulator. A hydraulic pump, belt-driven from the crankshaft, delivered hydraulic fluid into the sphere, pushing on the diaphragm and compressing the nitrogen. This pressure could be used to deliver fluid to the steering, transmission and brake/suspension systems.
Four more spheres were used in place of conventional suspension springs. As the wheels rose they forced fluid into the sphere, compressing the nitrogen – which acted as a soft, rising-rate spring. Fluid entering or leaving the sphere passed through a system of valves which provided suspension damping. The suspension units on each side of the car were connected to equalize the ride height from side to side. If a heavy load caused the suspension to droop, or the driver raised the ride height using the control lever, a height control valve introduced more fluid from the main accumulator to raise the body. Adding or removing fluid from the system adjusted the ride height or jacked the car up.
The advanced suspension was accompanied by centre-point steering – where the axis around which the wheel steered passed through the centre of the tyre/ground contact patch, minimising kick-back – and this combination gave the new car a remarkable ability to traverse rough surfaces and drive on flat tyres.
The brakes took fluid from the suspension system, causing a drop in ride height when they were operated. To avoid excessive front-end droop under braking a sixth sphere, the brake accumulator, was added to maintain the fluid level in the front suspension.
High-level brake lights were just one of the innovative ideas on the Citroen DS.
The structure and bodywork was just as innovative. A strong platform chassis with deep sills provided most of the structural strength, the suspension loads being fed into either end and the engine mounted between a pair of outriggers extending forwards from the front bulkhead. A skeleton bodywork frame, called the caisson, was attached to the platform and carried unstressed body panels. Inside, the innovation continued with a moulded plastic dashboard. Bertoni had proposed tiller steering, but settled instead for a radical single-spoke steering wheel.
The DS took the 1955 Paris Salon by storm. Spectators crowded around the Citroën stand, leaving the other exhibits deserted, and thrust handfuls of francs at bewildered Citroën salesmen: by the end of the first day 1000 orders had been taken, rising to more than 80,000 by the end of the show.
But early production cars were beset by problems with the hydraulic systems, caused by production line workers unfamiliar with the level of precision required by hydraulic systems. Cost was another drawback: the DS was considerably more expensive than the outgoing Traction Avant or any potential rival. In 1957 Citroën provided a solution to the cost issue, the ID19, which had a simpler interior and unassisted steering, along with conventional brakes, clutch and manual gearbox, and a detuned engine. An even cheaper ID Normale, with bench front seat but without a clock, heater, ashtray or even a passenger sun visor, proved unpopular. Much more successful was an estate version, known as the Break in Europe and Safari in the UK, which provided acres of load space together with the saloon's excellent ride and the benefit of self-levelling.
Regular updates included a reshaped front end which improved engine cooling, cut drag and boosted top speeds by up to 8mph, short-stroke engines and the introduction of a plush Pallas trim level. The hydraulic system was also switched from LHS fluid to LHM, which reduced internal corrosion in the hydraulic system and did not attack paintwork if spilled.
The most significant update was the restyled front end in September 1967, begun by Bertoni and, after his death, completed by Robert Opron. Self-levelling halogen headlamps were sunk into the wings behind glass fairings, along with long-range driving lamps which were mechanically linked to the steering rack so they aimed into corners. Further improvements included Bosch mechanical fuel injection and five-speed gearboxes, which were made available for the final few years of DS production. The big Citroën was finally phased out in 1975, but many of its innovations lived on in the new CX.
Driving a DS today is an unnerving experience because there is so much about the it which is so impressive, even by modern standards. The semi-automatic gearchange, for instance, is amazingly effective, offering fingertip gear selection which is swift and positive – its only demerit being sometimes jerky operation at very low speeds, making manoeuvring a chore. The zero-travel pressure-sensitive button which operates the brakes takes some getting used to, but the pressure required to operate the powerful brakes is no different to the often excessive servo assistance on a modern car. The power-assisted steering of the DS is conveniently weighted (the unassisted ID is more of a handful when parking) and all these cars have surprisingly good steering lock for a front-drive design of half a century ago. The hydropneumatic suspension makes all but the worst road irregularities imperceptible, and remains a remarkable achievement.
But the DS is not perfect. There's an unnerving tendency for the front end to dive under braking, and it's a shame the DS never got the flat-six engine that was originally intended for it. The long-stroke four in the early cars is noisy and unrefined, the later short-stroke engine smoother and more powerful, but none of the DS engines has the refinement that the rest of the car demands.
As a classic to own and run in the 21st century the DS is a good bet, as part and know-how are still available, but they rarely work out cheap. "It's a brilliant car if you find the right one, but a more difficult car to restore than most," says Paul Harris of DS Workshop, a Citroën specialist based in Potters Bar, Herts. "People buy £2-3k cars on Ebay and expect them to be sorted for £1500 – but it'll cost £15,000 to sort it out properly. It takes a hell of a lot of money to do the job properly." A full restoration, he says, could easily cost in excess of £35,000.
The DS never made money for Citroën, and on that score it ranks as a glorious failure. But as an example of what the automotive industry can achieve when bright, dedicated people have the vision to find and implement new solutions to problems, it remains unsurpassed.
Specifications
Citroën DS 1955
Engine 1911cc in-line four
Fuel system Weber carburettor
Power 62bhp
Torque 101lb ft at 3000-3500rpm
Transmission Four-speed semi-automatic gearbox, front-wheel drive
Steering Rack and pinion with hydraulic assistance
Suspension Front: leading arms, hydropneumatic spring/damper units, anti-roll bar Rear: trailing arms, hydropneumatic spring/damper units, anti-roll bar
Brakes inboard disc front, drum rear with powered hydraulic operation
Performance Top speed: 83mph; 0-60mph: 11-22sec.
Fuel consumption 24-30mpg
Values now £2000-£70,000
