Originally Posted by silverbear
Even a two speed would be great... something for low speed and hill climbing and the higher gear for normal cruising. Wouldn't that be great! Come on Jim, I'm ready to place an order.
I'm more concerned about the outcome "cost-wise" than the technicalities of making it work.
I don't think a deraileur will make a large jump, (2-speed); although you're right SB 2-speeds would work just fine...I just finished modeling up a 44, 40, 36, scenario, and I think that would work fine.
The main thing is that the chain is going to need to be fairly taught on the 44T for starting. In other words the deraileur/chain length will have to be adjusted so that there is very little spring action in the deraileur.
If the engine shut-off while riding on the 36T...it would be a problem as you would then be at full deraileur travel...i.e. a lot of potential slack on the bottom chain run. This could prove to be an annoying aspect of the set-up if the rider were not paying attention to gear selection before shut-off.
The system works, conventionally, when pedaled in forward motion...so I don't see a freewheel being critical to operation.
A sprocket adapter, with a 3-stack of 410 size sprockets, and a deraileur adapter should do it. This is, off course, over simplified as there would undoubtedly be a lot of adjustments to be made to get it to work just right.
I might try it...It should only take 2 days to prototype...now where am I going to find 2 days of free time.