Rear Wheel Not Spinning Freely

[Ian_M]

I have a Cab Motorworks Falcon, a Stealth Bomber style bike with a rear hub motor.
Recently I got a puncture, so took the wheel off, put in a new tube and reconnected the wheel, something I have done several times.
Now however, when I tighten the side nuts, the wheel will not spin freely. If I loosen the nuts, the wheel spins ok but its not rideable like that. I have checked everything I can think of.. made sure all the washers etc that were there before are back in the right place, have re-seated the wheel many times to make sure its sitting ok, centered etc. I have also removed the brake calipers to make sure its not the brakes rubbing. Nothing I seem to do makes a difference. its a constant grinding sort of sound, not a clunking which would suggest magnets inside the motor. Also the fact that it spins fine when loose means its mechanical somewhere.

Anyone got any idea what this could be?

 

[Voltron]

It's a maybe, but had a couple of customers that had gotten all the washers, but had dropped the cylindrical spacer that goes inside the freewheel. It will sit in there, then fall out un-noticed while you're fixing the flat?

 

[RunForTheHills]

My first guess would have been the brakes rubbing, but you eliminated that. Maybe the tire is rubbing on the fender if you have one or one of the seat stays.

 

[Voltron]

Here's what I meant.. The shoulder on the axle is down inside the freewheel, and needs to be spacered out with washers or whatever. If that is the problem...

 

[Voltron]

The guy PMed me fyi for anyone who gets the same problem...
It was a dropped spacer, and the frame was flexing in until it was hitting the freewheel without it, even though it was single speed.
On a regular bike you'd notice it in a repair stand as soon as you tried to pedal, but if you just hit the throttle for a second, it's less obvious since the wheel keeps spinning, but the bearings make lots of noise since they're all getting side loaded by the axle nut suddenly.