I have an idea for the bafang mid drives.

[Snurt]

I am terribly sorry if this is something suggested before or is just right out stupid, and I am also sorry that i have to use 1000 words instead of one picture, I cant draw.

If you make the Bafang BBS02's enginehousing and the BB part further apart with an adapterplate, then made the small cog on the engine drive the big cog with a belt instead of direct. This way the big cog thats connected to the shaft in the crank wil turn the other way around. Now you can install the BBSO2 from the left side of the bike, fit the motor inside the frame instead of under it and also continue to use your original chainring setup.

I hope you understood this, if not i have to try out my epic MS paint skills tomorrow to help visualize it.
I also hope it's not a stupid idea.

F*** it, epic paint skills incoming!
I just stole this image to make an example:


First you separate the engine and crank part:


Then you remove the original housing:


Then you make a adapter to replace original housing:


Then you add a belt or a chain(the red line represent it):


Now the engine wil fit inside the frame and the rotation on the crank should be reversed, so it can be installed from the left.

 

[d8veh]

It would be a lot easier and cheaper to use a geared hub-motor to drive the crank via a chain or belt.

 

[Asterix]

postby Snurt » Tue Oct 06, 2015 8:48 pm
I am terribly sorry if this is something suggested before or is just right out stupid, and I am also sorry that i have to use 1000 words instead of one picture, I cant draw.

If you make the Bafang BBS02's enginehousing and the BB part further apart with an adapterplate, then made the small cog on the engine drive the big cog with a belt instead of direct. This way the big cog thats connected to the shaft in the crank wil turn the other way around. Now you can install the BBSO2 from the left side of the bike, fit the motor inside the frame instead of under it and also continue to use your original chainring setup.

I hope you understood this, if not i have to try out my epic MS paint skills tomorrow to help visualize it.
I also hope it's not a stupid idea.

the BBS01 design is pretty successful in combining simplicity with low cost and robustness. If you enlarge the gearbox housing, you will increase the torsional stress on the bottom bracket shell.