This is a mount for a Rad Runner e bike that allows you to tow another bike behind you. I designed this for use with a mountainbike, which uses as 15 x 100 mm through axle but you can change the design to fit your bike. (Fusion files below)

Please print in a strong enough material with enough walls and infill. I am not responsible if you cause damage to your bike, yourself, or others.

Hardware

(12) M4 x 16mm bolt
(12) M4 nut