John in CR wrote:So you decided you wanted regen braking after all? What are you going to do about the mountains? Ready to cut me a deal on that heavy Nuvinci yet, since you don't need it any more unless there's another motor in the plan?
Yes, your point about saving the brakes on long descents by using regen made a lot of sense, and no the Nuvinci isn't being deleted, it is the Linchpin of this builld!
The reason for the "Hub Drive" title is because it's not a typical "mid drive" since the hub motor will be running a chain to the Nuvinci.
Dogman also made a good point about having a lock ring to keep the 14T cog tight on the hub motor under regen, and I have just the thing! An old BB lock ring threads right on.
It will make more sense once you see it coming together, but needless to say, once I have this put together, I will have a 1.57 to 1 single stage reduction from the hub motor (no wheel just the motor) mounted above the Nuvinci, and that will give me some serious low gears!
Oh, that reminds me, I forgot to show off my other find! here are some pics of the gears:
Here you see the new 74 BCD adapter (new to me, used from City Bikes in Portland) on the left that allows incredibly low chain rings to be mounted! I think it uses some form of freewheel cogs, but currently it has a 21T chain ring (this is where you mount the lowest chain ring on a typical MTB 3 chain ring crank) so I have some way to pedal up-hill with minimal effort in-case the electrics have trouble.
On the right you see the Surly 22T Track Sprocket, New Dicta freewheel and some no-name 14T track sprocket. These all bolt onto standard freewheel threads!
Here are some close-ups for the ultra low chain ring adapter. Anyone recognize this four point drive for the removable sprocket?