Ebike friction drive unit

Update 24.03.2019
Now as the weather is getting better I had a chance to test the e-drive in real.This this thing accelerates as hell with a 4S battery and the motor and the ESC is good for 6S. The test reult is that the position of the drive unit to the wheel is very important , if it is too high than it can jump over as the tires got pressed. To prevent this an end stop will be needed. Probably a small (RC car size) shock absorber is also a good option. The gear mesh is good and the gears are strong enough for this motor.

This is work in progress, at the moment only a proof of concept only the 2. sprint of the project.

This thing is a drive unit to convert a mountain bike to ebike.
Design goal is to make a fully 3D printable drive unit what can be fitted to a mountain bike in limited space. The unit shall not serve for long rides but only as a booster on a few slopes.
The bike I use for testing is an old 26" woman bike. The unit is using RC hobby electronics what are ava