A Century of Cars: 13. Solido 1939 Citroen 15CV Traction Avant
The Traction Avant, or front drive, was
designed by André Lefèbvre and Flaminio Bertoni in late 1933 / early
1934. While not the first production front wheel drive car it was
the most successful.
Not only was the Traction Avant's drive train innovative, so was its arc-welded monocoque (unitized body). Most other cars of the era were based on a separate chassis onto which the non-structural body was built. Monocoque construction results in a lighter vehicle, and is now used for virtually all car construction, although body-on-frame construction is still suitable for larger vehicles such as trucks.
This method of construction was viewed with great suspicion in many quarters, with doubts about its strength. A type of crash test was developed, taking the form of driving the car off a cliff, to illustrate its great inherent resilience.
The novel design made the car seem very low-slung relative to its contemporaries the Traction Avant always possessed a unique look, which went from appearing rakish in 1934 to familiar and somewhat old fashioned by 1955 when it was withdrawn.
The suspension was very advanced for the car's era. The front wheels were independently sprung, using a torsion bar and wishbone suspension arrangement, where most contemporaries used live axle and cart-type leaf spring designs. The rear suspension was a simple steel beam axle and Panhard rod, trailing arms and torsion bars attached to a 3-inch (76 mm) steel tube.
Since it was considerably lighter than "conventional" designs of the era, it was capable of 100 km/h (62 mph), and consumed gasoline / petrol only at the rate of 10 litres per 100 kilometres (28 mpg-imp; 24 mpg-US).