I have considered cutting a larger hole on the right side, perhaps twice the diameter of the 6-hole disc brake BCD. And then I would attach the motor-sideplate to a thinner steel sub-plate (perhaps using a 5-hole 130-BCD chainring as the hole-drilling jig?). I may still do that if chain alignment issues force it to be done (doing this would expose more of the motor shaft on the right side, and move the motors' left side inward an equal amount).
I am frustrated by how much time that unexpected issues in my personal life keep me away from finishing this. Once done, I can order several kits to sell to any interested parties to recoup the modest development costs. There is a big price break from bigbluesaw.com at 10 pieces, so I am trying to design the two sides to work using an identical shape, which would limit my risk to only needing to sell 5 kits.
Once done, and this drive has been verified to work well (see the similar drive already finished by waynebergman viewtopic.php?f=28&t=49467
), It would be a fairly quick process to simply order more water-jetted parts, and then re-package to ship to customers. If there were no unexpected issues, a kit might be able to be delivered three weeks after being ordered. If demand was consistent enough, I could begin stocking kits for a more rapid delivery...but that evaulation is a few months away...
The input from crossbreak, greenmachine, and waynebergman has been extremely valuable...I thank you all. The BPM is slightly narrower at the stator/magnets (which is the reason for the MACs higher power potential), and it may prove to be easier to use in a BB-drive. I have yet to know if I will need crank-arms with more off-set than the common shape.
Fixed sprockets for the output shaft from the motor to the rear wheel sprockets can be easily and cheaply found with 16T-22T tooth-counts, using the ID interface of the IGH 3-tabs, or the common 1.38 X 24 freewheel threads, or Shimano cassette splines. I am hoping to avoid using an 11T sprocket for top speed on the rear gear-cluster (probably a 7-speed), but in order to use a larger set of gears in the back, I must also raise the tooth-counts on the motor-drive sprocket (if I am to maintain the same ratio).
In order to reduce the tooth-loading on the rear sprockets, I hope to use a 15T-34T 7-speed sprocket set. These seem to be the largest that are easily available at reasonable prices (for replacement when worn). jateureka posted that 24T and 26T sprockets are now available
using the IGH 3-tab bore interface (http://bikesmithdesign.com/cogs/index.html
), so I might try those first. I also like how the larger motor-sprocket (26T instead of 22T) will provide slightly more chain clearance from the crank-arms.