Anybody ever thought of using one for an e-bike? They're reasonably light, they've already got a twist throttle, they spin at about the right speed. Downsides are that they're designed to be water-cooled and the bearings aren't designed for side loads.

Thoughts?

I think you already thought of the bigest downside of them. Lets face it by the time you solve the cooling problem and the high RPMs and small shaft and building a way to mount it to a bike you could have gotten a good RC motor setup.

Bob

Why bother. Pick the low hanging fruit. Get a decent brushless hub motor, a cheap Chinese controller, say, from BMSbattery.com, and as much battery as you can afford. You won't be sorry. Why does everybody try to re-invent "solutions" when there are thousands of people out there with the "EV grin" already. Simple, no issues. And don't forget the torque arms.

Well, I'm enough of a redneck I already have two trolling motors I'm not using. But you do bring up some good points.