Skarper, the disc you already own

Skarper drives the rear disc instead of a hub or a bracket. Riders who have spent money on a wheelset look at it for that reason. The bike needs a disc brake and a chainstay the mount can use.

The fit on this site is specialist. The puck and the caliper share a corner of the frame. A rim-brake bike is not a candidate.

240 Wh is a real pack, larger than the Zehus hub and smaller than a big downtube. The class is 250 W. Price was not confirmed, so it is Maker list.

Read the rotor size and the pad clearance with the unit offered up, not from a hero photograph.