found a site where the double chain gearbox is pretty well spelled out, a couple extra chains might be avoided if you have two sprockets on the rear wheel/axle, and/or can drive the input shaft directly. Anyway it might offer some ideas for small EV'ers to be able to climb hills AND have decent top speed (and a neutral) hopefully without the losses of a belt/pulley.
Widdershins Way - DIY Gearbox
