As per Sick Bike Parts themselves: RequirementsOK!
I'm really very new to this, as I've stated in other posts. Nevertheless, after having read up on all this for the last 2 or 3 days it occurred to me that I would like to build a motorized bike with the shift kit and an internal shift hub. I was about to start a new thread asking about this when I came across this one.
My concerns were exactly dealing with the stresses on the hub and how durable it would be when subjected to a motor drive.
Excellent thread!!!
Please keep us up to date on your findings.
If you haven't built a motorized bike before you should start with that. Buy a kit, Install it, Once you have it running smoothly and you feel confident in your abilities then install the Shift kit.