So what’s so great about the 2cv anyway? Critics rightfully claim that it is rusty, noisy, and slow. However cognoscenti know that it is one of the best examples of minimalist engineering and has advanced features that are only now being incorporated into today’s cars.
One of these features is a sandwich platform chassis, which has only recently appeared on cars like the Mercedes A and B class. Yes, rust is a source of frustration with the deuche implementation but it can easily be prevented with today’s modern materials and coatings.
This platform chassis provides great strength for its weight and is structurally efficient. It is essentially a wide flange beam with plenty of load-carrying material in the upper and lower fibers. The suspension and spring mounts at each end of the beam are located very close together (approx 6’6”) unlike many other cars where the mounts are located way out in the wheel wells. Because the beam is so short, it can be much lighter to carry the working loads. To boot, the suspension design routes the spring and shock loads horizontally along the platform where they help to counteract passenger loads on the platform. For example, when the car goes over a bump the lower fibers of the platform are in tension. However, at the same time, the springs are in compression and tend to counteract the tension.
In addition, this strong platform which forms the floor of the passenger compartment helps to keep the compartment intact during a frontal collision with the overhanging front spars of the chassis collapsing to absorb impact energy. Pierre Boulanger did not have this in mind when his team designed the 2CV, but there you go, sometimes there is serendipity. Frontal crash tests support this thesis.
Another novel feature of the deuche is the soft springs and huge suspension travel. Colin Chapman, designer of Lotus cars, proved that soft springs and long suspension travel are key ingredients for good handling. The deuche has both soft springing and incredible amounts of travel. However, Colin also included careful and progressive damping as one of the ingredients, which are marginal on the deuche. Two out of three ain’t bad.
Inboard front disk brakes like those on the deuche appeared on formula 1 cars for a few years. The idea was to reduce unsprung weight and improve adhesion on bumpy surfaces. These disappeared after a while because of the difficulty of cooling the disks under racing conditions – definitely not a problem with the slow deuche under daily driving conditions. In addition to the low unsprung weight, the inboard disks obviate the need for flexible hoses which can contribute to a mushy pedal feeling. But the big advantage is that the front brakes are out of the wheel spray and guck which contributes to longer brake life.
The deuche was designed before air conditioning. To keep occupants cool, the deuche has a wonderful vent below the windshield coupled with a roll-up roof. I have ridden in a deuche on a hot summer day with the vent open and the roof rolled back and been very comfortable. So, why eat up valuable gas to run an air conditioner? The only improvement I might make would be to install a 60% shade screen like they do on lettuce farms to let the air pass through without having the sun burn a hole in the top of your head.
Now about that 2-cylinder engine. Car manufacturers such as FIAT and Hyundai are moving to fewer cylinders and smaller engines to reduce weight, friction losses,and improve gas mileage while cruising. In fact, FIAT’s new “500” can be purchased with a 2-cylinder engine. The 2 CV has 2 cylinders but, unlike the FIAT, requires no balance shaft to reduce vibration. The difference with the modern cars is that they achieve much more peak horsepower for acceleration by means of turbochargers. I am unconvinced that the extra cost and complexity of the turbocharger is worth the increased cost and reliability concerns introduced by a turbocharger. Also, how much acceleration do you really need?
The car’s light weight and small engine contribute to excellent fuel economy that surpasses that of many modern cars, and all from an engine design that is almost 60 years old.
The rear opening and flat floor let you slide long boards into the car and close the trunk lid. Try that with a small modern car. That feature is only usually available in much larger mini-vans and SUV’s.
So lets hear it for the intelligent features built into the deuche and hope that modern car designs will use them.