BBSHD has quite a bit of resistance when pedaled un-powered

kiltedcelt

100 W
Joined
Aug 19, 2015
Messages
158
Location
Chicago, IL USA
Title says it all. I've had the motor about a year or so and when it's under power it works flawlessly, however when the battery gets critically low and the controller cuts it off or you just try pedaling without the motor on, the resistance is so great you pretty much have to use the lowest gears on the cassette to move the thing forwards at 10 mph. It freewheels fine in reverse so I don't think there's an issue with the clutch, but I have read a few inconclusive threads about resistance being caused by something to do with the nylon gear. Does anyone have a definitive cause for this excessive un-powered pedaling resistance and how to address it or what replacement parts might be needed? I've installed this motor on my tandem trike project and would like to address this issue so I'm not struggling to pedal in case there are battery issues or anything else down the road and I need to pedal in un-powered mode.
 
If you pedal hard, driven wheel offground, with the battery voltage very low, do you see the battery voltage go up at all, even a tiny flicker? If so, the resistance is the pedals backdriving the motor.

If not, then the resistance would have to be mechanical in some other way, like a bearing problem of the crankshaft itself, etc.

Or...it could be a problem with the driven wheel or chaindrive itself. How much power does the motor take to spin the wheel offground, vs how much resistance the pedals have with the wheel offground?
 
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