Many years ago I had an early CZ jawa 250cc 1947 I think.
I'm sure it had interchangeable front and back wheels.
You just undid the axle nut and dragged the axle out and there were spacers and the brake drum moved to one side. On the back wheel the drive chain stayed put and the brake drum moved out of the way and there was a rubber block or star shaped setup inside the hub that connected the drive to the hub.
Has anyone else come across this?
TommyG