Da vinci (and discovery channel) solved my gear problem.

I was watching Da Vinci's Machines for the first time and saw the Armored car (with canons, so I guess it's really a tank). The tank is driven by a very engenious stretched gear system, which is perfect for my dragon.

The principle is to build a cage, which will be rotated by the pegs in the big wheel. Another cage on the other side will drive another wheel. This way the rotation of the wheels is synchronised with a minimum of gears.
Da Vinci used this to transfer the movement from the middle to both sides simultaneously, but this principle will work in threefold for my dragon.