Home 2CV History Construction

The level of technology in the 1948 2CV was remarkable for a car of any price in that era, let alone one of the cheapest cars on the planet. While colours and detail specifications were modified in the ensuing 42 years, the biggest mechanical change was the addition of front disc brakes in 1981 (from the discontinued Citroen Dyane), for the 1982 model year.

 

The 1948 2CV featured:

 

  • four wheel independent suspension that inter-connected front to rear on the same side,
  • leading arm front suspension,
  • trailing arm rear suspension,
  • rear fender skirts, but the suspension design allowed wheel change without removing the skirts,
  • front-wheel drive,
  • inboard front brakes, in order to help lower unsprung weight thus making ride even softer.
  • small, lightweight, air-cooled flat twin engine,
  • 4-speed manual transmission,
  • bolt-on detachable front and rear wings/fenders,
  • detachable doors, bonnet (and bootlid after 1960)—by "slide out" P profile sheet metal hinges,
  • front rear-hinged 'suicide doors',
  • flap-up windows, as roll up windows were considered too expensive in 1948,
  • detachable full length fabric sunroof and boot lid—for almost pickup truck type load carrying versatility.

The body was constructed of a dual H-frame chassis, an aircraft-style tube framework, and a very thin steel shell.

The suspension of the 2CV was almost comically soft—a person could easily rock the car side to side dramatically (back and forth was quite a bit more resistant). The leading arm / trailing arm swinging arm, fore-aft linked suspension system together with inboard front brakes had a much smaller unsprung weight than existing coil spring or leaf designs. The interconnection transmitted some of the force deflecting a front wheel up over a bump, to push the rear wheel down on the same side. When the rear wheel met that bump a moment later, it did the same in reverse, keeping the car level front to rear. This made the suspension more responsive, enabling the 2CV to indeed be driven at speed over a ploughed field. Since the rear brakes were outboard, extra tuned mass dampers and later shock absorbers were fitted to the rear wheels to dampen wheel bounce. Later models had tuned mass dampers at the front with telescopic dampers / shock absorbers front and rear. The 2CV suspension was assessed by Alec Issigonis and Alex Moulton in the mid-1950s, (according to an interview by Moulton with CAR magazine in the late 1990s), which then inspired them to design the Hydrolastic suspension system for the Mini and Austin 1100, to try to keep the benefits of the 2CV system but with added roll stiffness.Front-wheel drive made the car easy and safe to drive and Citroën had developed some experience with it due to the pioneering Traction Avant.

It was powered by a flat-twin air-cooled engine designed by Walter Becchia, with a nod to the classic "boxer" BMW motorcycle engine (it is reported that Becchia dismantled the engine of the BMW motorcycle of Flaminio Bertoni before designing the 2CV engine).

 

The car had a 4-speed manual transmission, an advanced feature on an inexpensive car at the time. Boulanger had originally insisted on no more than three gears, because he believed that with four ratios the car would be perceived as complex to drive by customers. Thus, the fourth gear was marketed as an overdrive, this is why on the early cars the "4" was replaced by "S" for surmultipliée. The gear shifter came horizontally out of the dashboard with the handle curved upwards. It had a strange shift pattern: the first was back on the left, the second and third were inline, and the fourth (or the S) could be engaged only by turning the lever to the right from the third.

In keeping with the ultra-utilitarian (and rural) design brief, the canvas roof could be rolled completely open. The Type A had one stop light, and was available only in grey. The windscreen wipers were powered by a purely mechanical system: a cable connected to the transmission; to reduce cost, this cable also powered the speedometer. The wipers' speed was therefore variable with car speed. When the car was waiting at a crossroad, the wipers were not powered; thus, a handle under the speedometer allowed them to be operated by hand. From the 1960s this was replaced with an electric motor.

The reliability of the car was increased by the fact that, being air-cooled, it had no coolant, radiator, water pump or thermostat. It had no distributor either because both spark plugs were fired at the same time, on every 360 degree rotation. Except for the brakes there were no hydraulic parts on original models as the shock absorbers were replaced by tuned mass dampers and friction dampers.