Need help understanding my ebike

[pengyou]

I have a nondescript Chinese made 48v, 240 watt motor ebike. I do not completely understand how the controller interfaces with the pedaling/crank. When i start pedaling it is really difficult sometimes. Sometimes when I pedal it is easier. Lately a few times, however, when I have pedaled from a standstill there has been absolutely no resistance at all, which worries me. I get the impression that there is some kind of electric clutch inside the crank area....can any shed some light on the subject?

[cerewa]

Can you post pics of the bike? Or alternatively generic pictures of that model of bike?

[pengyou]

and now....heeeerrress bikey!

[cerewa]

I have some doubts that it is actually a clutch.

The thing that makes me doubt it's a clutch (electrically-controlled or not) is that for a bicycle/e-bike, a clutch is likely to be just a little bit too complicated, heavy, and unnecessary for somebody to install one. I believe the website http://howstuffworks.com has a good article on how automobile clutches work. You could also search for info on how a "centrifugal clutch" works-- a centrifugal clutch is what's commonly used on ATVs and other things powered by tiny gas motors. I can think of almost no benefit you could get from the pedals powering the bike through a clutch rather than through a freewheel.

It seems possible to me that what you actually have is a malfunctioning freewheel, if you have not definitively figured out that it isn't a freewheel.

I am assuming this is not the case, but it would be possible to have the pedals drive the hub-motor by turning an electric generator inside the hub that then powers a motor inside the hub. While it would be possible to do this, I think it would also be a stupid design... but one that might produce the problem you describe. The advantage of this design would be that it could serve as a substitute for multi-speed gearing... probably a very poor substitute.

If you feel up to the task, you could learn a lot by disassembling the rear hub and looking at what you see. If you do take it apart, feel free to post pics of it, since it might help someone figure out what's wrong with your bike.

[pengyou]

Yes, if there was something wrong with the freewheel that would explain the problem. It is an intermittent problem though.

[Leisesturm]

Yes, if there was something wrong with the freewheel that would explain the problem. It is an intermittent problem though.


I also think it is a freewheel issue. I wouldn't think the freewheel is in the hub though. There might be a freewheel on the crank so that it can remain stationary while the motor drives the bike and/or vice versa. Dirt and/or old grease is sticking the pawls in the freewheel(s). The crank assembly needs to be opened and degreased. The hub probably needs to be inspected but it is the freewheel outside of the motor itself that is suspect. That is not as clear as I could make it but it is as clear as I could make it right now.

H