Has any manufacturer ever constructed a combination fixed rear hub that can also turn into a freewheeling single speed rear hub with handlebar type activation? This goes back to a conversation with a local that supported the value of such an animal. You would have the efficiency of a fixed, but at a moment's touch you could also freewheel down a hill or freewheel in traffic making caliper brakes easier to judge. I thought that such a device might have been designed at one time or another due to how simple it would have been to engineer, but I could not recall a discussion of it in any book or forum.
Garth Libre in Miami Fl.