Reader's Search: "why are 2CV good off road [sic]"
Here's a Search Query I saw in the logs of Carcynic.com recently:"why are 2CV good off road". It may not be good grammar, but it's a good question (Actually it's 2 questions, as we will see), so I thought I'd answer it even though our inquisitive web searcher has come and gone.
Just like in Hitchhiker's Guide to the Galaxy, we need to look more closely at the question. Was our inquisitive surfer asking "Why where Citroen 2CV's designed to be good off road?" or were they asking "What is it mechanically about 2CV's that make then good off-road?".
Bandwidth is cheap, so I'll answer both.
European rural roads were not great even before World War II. They were generally what we would call "unimproved" roads. Then, during the war, may were quite heavily bombed. Dropping bombs on something generally counts as further "unimproving" it. The 2CV was designed for those living in rural France, and thus had to be designed for use on "unimproved" (i.e. pretty much non-existent) roads. If you guessed that those living in rural France in the late 1940's/early 1950's were Web Designers or Video Game Developers, you're -- uh -- well, let's just say you're incorrect. Most were farmers. Now a farmer is not going to take his herd of cattle to market in a car like the 2CV, but he did still need an efficient way to transport smaller goods. One of the most delicate such commodity being fresh eggs. This lead Andre' Citroën himself (allegedly) to come up with the requirement that the 2CV "..shall be able to transport a farmer and his wife across a plowed field while the wife has a basket of eggs on her lap, without any eggs breaking."
Since these days most of us don't farm, I want to be clear on what a plowed ("ploughed" outside the US) field is. It does not mean "smoothed", and certainly not packed. A plowed field has large ruts cut by the plow, and loose, freshly turned dirt in preparation for planting. Driving across a plowed field is not like just driving down a dirt road.
So how did they meet this requirement? What mechanical features of the 2CV give it it's nearly monster truck off-road prowess? First, the 2CV (and it's derivatives, such as the Dyane, Mehari, and others) have lots of ground clearance. With their leading/training arm suspension, there is no axle crossing under the vehicle to "ground" on rocks and obstacles. They are also very light, so that they have less of a tendency to sink into soft ground. The left-to-right independent suspension, with a lot of travel, also helps to insure that both drive wheels stay in good contact with the ground. A vehicle like a Jeep, with solid axles, will often lift a wheel when going over uneven ground. The fact that the 2CV is front wheel drive also helps significantly. Not only is the weight of the engine (and driver to some extent) over the drive wheels, but since the drive wheels approach obstacles first, they have a better chance of climbing over them.
A few other features, such as having the carburetor mounted high over the engine, also help off-road survival. The Battery, Ignition coil, alternator, and most of the electrical system is also kept high, so puddles and small streams don't cause shorts.
Now, there were specialized versions of the 2CV (such as the 2-engined 2CV Sahara) with 4 Wheel drive, and even today, may people build specialized 4x4 2CV-based off-roaders, but even a "stock" 2CV is going to perform far better off-road than it's modern economy equivalent like a Honda Fit, or a Toyota Echo.