Chainwheels

So if I understand the picture, the motor will turn the sprocket and the cranks and the freewheel is so the motor doesn't spin while you're pedalling. Wouldn't the better arrangement be to have the cranks still while the motor is running?

Probably right with that last part, but if it's a low power kit then I see why it would have the cranks spin with the motor.

It's my understanding that the motor turns the sprocket it's connected to which then turns the chainwheel that turns the rear freewheel/hub and the front freewheel keeps the cranks from turning. Why would you want the cranks to run with the motor? It would break your legs or give you some serious bruises.

You have got hold of the wrong end of the stick! Both chainwheels are bolted together they cannot turn independently, the motor drives one, the other drives the wheel, pedals don't go round. you can catch the motor up and pedal at any time. there will be another freewheel on the motor so if you pedal when not under power the motor chain will go round but not turn the motor.

It looks to me like the usual setup, a freewheel in the crank. So you can run the motor with or without pedaling.

I'm not positive what happens if you pedal with no motor. Does anybody really do that? I always want at least a 75w assist to overcome the extra weight of the battery and motor.

wesnewell said:

Why would you want the cranks to run with the motor? It would break your legs or give you some serious bruises.

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Well, as my post says, I DON'T want it to, but it sure looks like it would. I don't see how the main sprocket has been freewheeled from looking at it. I suppose if you do some grinding on the original sprocket you can fit the freewheel in there. . . .

I was just hoping someone was familiar with this particular kit and could say for sure.

In the picture the smaller crank sprocket is mounted to the flange of the freewheel via the 5 small fixings, the larger sprocket is bolted to the smaller one by the 4 larger fixings, neither of the sprockets are mounted directly to the pedal cranks in the conventional way.

http://www.google.co.uk/imgres?imgurl=http%3A%2F%2Fwww.cyclone-tw.com%2Fimages%2F444432freewheel-crankBB-s.jpg&imgrefurl=http%3A%2F%2Fwww.cyclone-tw.com%2Forder-chainwheel.htm&h=177&w=200&tbnid=PHs8BTvW_MnGYM%3A&zoom=1&docid=v48ILi9wVHTNpM&ei=3vtMU5bBKqrV0QW9u4CQAw&tbm=isch&ved=0CGUQMygOMA4&iact=rc&uact=3&dur=611&page=1&start=0&ndsp=16

Unless I'm hopelessly confused, when the motor turns both sprockets turn and drive the chain. But the freewheel inside the assembly allows the pedals to remain stationary. If the sprockets are turning fast enough, you might not be able to pedal fast enough to engage the pawls of the freewheel. It might freewheel till you pedal harder, and catch up with the motor.

The freewheel is never allowing one sprocket to turn, but not the other. Both sprockets turn if the motor runs. Both sprockets turn if you pedal with the motor off. It can still coast though, by using the rear gear freewheel, if there is one. Coasting, the chain will not move, nor the pedals, just like normal for most bikes.

Well, I hope you're right. The look struck me as odd and I can't see it working that way, but that of course is the best way.

what is more confusing is why is the swingarm tied to the main frame.. unless the motor is also on a pivot.

gwhy! said:

what is more confusing is why is the swingarm tied to the main frame.. unless the motor is also on a pivot.

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Are you talking about the motor arm that is bolted with the shock? I suspect that has to do with it being the ONLY place available to attach it. Not that it's a great idea, but I assume it's necessary. Maybe it's just the wrong bike to use.