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Using a hub motor as a mid drive

Joined
Jun 22, 2020
Messages
13
Hi,

I am searching for a way to effectively replace a belt reduction mid drive motor. I am thinking through the feasibility of using a high torque geared or direct drive hub motor, finding parts to mount it on a frame, and have the motor drive one chain ring, and the second chain ring drive the rear 20" wheel with a derailleur. Basically a Stoke monkey, second generation, but with 2 chains rather than 1 long one.)

I have on my Cargo bike already a freewheel crank set with 2 44t chainrings. 36v battery.

The first question I have is if it is possible to reverse the direction of a hub motor. I know DC motors can reverse direction by changing the polarity, but is it the same for a motor with a controller?

this is the motor that I am thinking of mounting. https://www.ebikekit.com/collections/wheels/products/rear-500w-heavy-duty-direct-drive-motor

Id be thankful to receive helpful advice or reasons as to why not to go this route. Attached is what I currently have, but I snap the belts constantly.

Thanks,
Kein
 

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Kein Kochendes said:
The first question I have is if it is possible to reverse the direction of a hub motor. I know DC motors can reverse direction by changing the polarity, but is it the same for a motor with a controller?

Yes; you can either swap two phase wires (with non-smart controllers) or programmable ones you just flip the motor direction toggle in software.
 
I saw this design online a while back, which uses a hub motor midway between crank and rear axle. Seems like one would need a one way clutch in there someplace. Is this similar to what you are describing?

https://evnerds.com/wp-content/uploads/2017/08/cruiser-ebikes_mis.jpg

This setup is one of several used by Ludovik ebikes, which was located in Kiev Ukraine. Not sure if they are currently active.
 
Yes, close to that. Except the motor would drive the 1 chainring, and the 2nd chainring on the crankset would drive the wheel. From what I think, the motor would have to go in reverse, and the direction of the freewheel on the motor would need to be opposite to the common BMX freewheel.
 
Why don't you just install a Bafang BBSHD motor?

A Leaf DD motor is another option.

A MAC geared hub motor is a third option.

If you need a mid drive so you can change the gearing the Bafang BBSHD would be much simpler. If you ride at speeds of 28 mph or slower, I'd go with a MAC 12T or 10T motor...or a GMAC from Grin Tech. If you want speeds above 30 mph, use a DD motor. Everything I am mentioning would be rear wheel drive.

You can use a DD motor or a Geared Hub Motor as a mid drive but why go through all the headaches if there are much simpler options?
 
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