The adapter threads on to axles with an M12x1.25 thread.

The Robert Axle Project Trailer Hitch Adapter for Rad Power Bikes and Mahle/EBIKEMOTION Equipped E-Bikes. Our hitch adapter for towing kid trailers and single-arm bike trailers is high quality and precisely machined. This includes all the two-wheeled child, pet and cargo trailers such as: Thule, Chariot, Burley, Instep, Carry Freedom, and many more.

Our hitch adapter is made of stainless steel and is incredibly durable. Its built to handle towing a fully loaded bike trailer. It easily clears a variety of dropouts. It is easy to install. Simply replace the existing non-driveside nut with our adapter, and attach the hitch that came with your trailer.

Our hitch adapter uses a 17 mm wrench to attach your hitch and precious cargo more securely than with other knurled adapters. When installing the hitch, the 17 mm wrench isolates and protects dropouts from marring and over-tightening.