Hub installed on bottom bracket

I've searched around but can't find any examples where someone has installed a hub motor directly to the bottom bracket. So the hub case spins as usual and has a sprocket attached, which drives the chain. Kind of a 'direct' mid drive.

There are plenty of disadvantages with this method compared to a normal mid drive with multiple chains, but I'm still interested in this style of build for a few reasons.

My goal would be a light 2 kg hub motor with the axle attached to the bottom bracket. Then a sprocket that runs the normal bike chain through a rear derailer. And then the motor itself, with some clamping on the outside that runs up to the frame.

Maybe in the future a dual chain version that has 6 kg motors on each side and drives a motorcycle chain through fixed (non-freewheel) sprockets.

I wish there was a way to convert a hub motor so the stator moved instead of the case. Otherwise it's hard to find something with a nice low kv in the 5 - 20 region.

Look up Crossbreak's thread; he's done that conversion on a geared hub.


Somewhere else someone wanted to do a DD hub the same way and I replied with a way to do that. I don't have a link but you might find it in my posts searching for crossbreak.

Is this what you are trying to describe?

https://www.bikeebike.com/

thepronghorn said:

Is this what you are trying to describe?

https://www.bikeebike.com/

Click to expand...

Very interesting.
Has anybody tested one yet , compared to the Bafang Max/Ultra etc ?

There's this. I wonder how much it would be for just the motor...

https://endless-sphere.com/forums/viewtopic.php?f=28&t=90548&hilit=bikee