The Citroën Prototype 2 CV TPV from 1939, two cylinders, 375 cc, three speeds, 50 km/h
In 1936, Pierre-Jules Boulanger, vice-president of Citroën and chief of engineering and design, sent the brief to his design team at the engineering department. The TPV (Toute Petite Voiture – “Very Small Car”) was to be developed in secrecy at Michelin facilities at Clermont-Ferrand and at Citroën in Paris, by the design team who had created the Traction Avant.
Boulanger closely monitored all decisions relating to the TPV, proposing strictly reduced target weights. He created a department to weigh and redesign each component, to lighten the TPV without compromising function.
Boulanger placed engineer André Lefèbvre in charge of the TPV project. Lefèbvre had designed and raced Grand Prix cars; his speciality was chassis design and he was particularly interested in maintaining contact between tyres and the road surface.
The first prototypes were bare chassis with rudimentary controls, seating and roof; test drivers wore leather flying suits, of the type used in contemporary open biplanes.
By the end of 1937 20 TPV experimental prototypes had been built and tested. The prototypes had only one headlight, all that was required by French law at the time. On 29 December 1937, Pierre Michelin was killed in a car crash; Boulanger became president of Citroën.
By 1939 the TPV was deemed ready, after 47 technically different and incrementally improved experimental prototypes had been built and tested. These prototypes used aluminium and magnesium parts and had water-cooled flat twin engines with front-wheel drive. The seats were hammocks hung from the roof by wires. The suspension system, designed by Alphonse Forceau, used front leading arms and rear trailing arms, connected to eight torsion bars beneath the rear seat: a bar for the front axle, one for the rear axle, an intermediate bar for each side, and an overload bar for each side. The front axle was connected to its torsion bars by cable. The overload bar came into play when the car had three people on board, two in the front and one in the rear, to support the extra load of a fourth passenger and fifty kilograms of luggage.
In mid-1939 a pilot run of 250 cars was produced and on 28 August 1939 the car received approval for the French market. Brochures were printed and preparations made to present the car, renamed the Citroën 2CV, at the forthcoming Paris Motor Show in October 1939.
One innovation included from the beginning of production was Michelin’s new radial tyre, first commercialised with the introduction of the 2CV. This radial design is an integral part of the design of the 2CV chassis.[
