[JesseK]

This setup makes it somewhat difficult to attach bumpers outside of the wheels, particularly with 8" wheels and bumpers that have a very specific 'zone' of placement. The Poofs get away with this by mounting their chain on the inside of the wheel rails, allowing them to mount metal brackets to reach the outside for bumpers -- is it possible to do the same with the gears?

I'm also not sure that the setup would weigh 56 lbs; if it's an issue you may want to double check it, or investigate using other materials for gears (or thinner gears).