Originally Posted by
kmcrawford111
Also, any idea of how well the system would work with a single-speed freewheel?
Since the bike is IGH I would have to use a SS freewheel. I don't know if it's even possible to add a rear deraillieur, but I like the idea of the SS anyway - having just one speed adjustment (the assist level) to think about. I just hope the pedalling works OK with the assistance since I'll be stuck at one unassisted speed. The current cog on the IGH is 20-tooth and I know how the drive is there since IGH speed 5 is a 1:1 gear ratio. I'm thinking that with BionX I might want to start with 22 teeth to compensate for the additional weight. One nice thing about this setup would be that it wouldn't be terribly heavier since the IGH is heavy itself and would be removed in the process.
It won't work. Not unless you get the chain line perfect. If not, the chain will just fall off. Go to the SS/FG area if you want more people's opinion on how to do this. Also, how will you keep the chain taunt - running an idler wheel?
Bafang CST is the only one that I know of that will take the regular shimano mountain bike cassette. Otherwise, you are typically looking at a 6 or 7 speed freewheel.
If you can get the chainline and chain tension addressed, it could work, but it is likely to be a headache getting the chainline right, unless you have a lot of flexibility in placing the cog. You could get a Bafang CST, and then a single speed adapter kit where you can place the cog anywhere on the spindle, then add an idler wheel for chain tension.
You get that chainline just a little off, and the chain will pop off. You could get the drawings of the motor and take some close measurements and then cross your fingers...