.02, noting a newer hub made by Sram, offers a screw in fixed- freewheel option,
so having a screwdriver along , would let the change happen mid ride..
what caught my attention was the use of a driver that took 3 speed cogs .. cheap and commonplace.
13 to 22t.. so that (and a fixie velcro strap on the pedals ) would be a possible wheel build upgrade.