Using rear geared hub as mid-drive - feasible, or a bad idea?

[pn_day]

Hi all,

Questions at the bottom for those with little time.

I had a bad spill a few weeks ago - smashed my collarbone into multiple pieces, and have been laid up recovering for several weeks. Unfortunately my lovely wife has therefore decided that cycling is dangerous. I'm considering using it as an excuse to get a recumbent trike, and if so, options for adding a crank drive motor to it in the cheapest manner possible.

I currently have an 8fun/Bafang 500W CST hub motor, which I've been running for the last 1500 miles without problems (apart from me coming off!)

I was therefore wondering if I could use this, in conjunction with a freewheel crank and suitable mounting brackets to drive the front crank.

1. Is this possible?

2. Does the whole hub rotate, or does the mounting bracket have to be fabricated to use the spoke holes to force it to be stationary?

3. Or is it more sensible to just sell the CST motor and controller, and buy something like the Bafang BBS 01/02? I want to keep the front derailleur so understand this would require some work to modify the BBS unit.

4. Any other better ideas on how to add a mid drive motor to a recumbent trike?

Many thanks
Phil

 

[Deleted member 4366]

You can use it as a mid-drive, but it's quite a big motor for that (width and diameter). What's wrong with putting it in the back wheel?

On a recumbent, the way to do it would be to use it as a jackshaft, with the chain from the chainwheel on one side and run a chain on the other side to the rear derailleur. You fix a sprocket to the disc mounting holes.

 

[Geebee]

Look up stokemonkey, I ran a small hub to the cranks on a recumbent trike which worked quite well but the pedals spun with the motor so get the gearing right to have an 80 rpm crank or preferably less.
Best bet use it as a hub and buy a BBS01 or similar for the crank drive, lighter, better control, free wheeling pedals and a bout a million times easier to get working and if you hunt around fitting 2 rings should not be to hard.

Sample link to a Stokemonkey, there are many DIY versions.
http://www.ebikes.ca/product-info/stoke.html

 

[pn_day]

Thanks both. I think you are right - it is a big motor. I'll save for a BBS0x unit. Cheers


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