i recently started wearing a few bumper again. obviously vintage.
it seems that bumpers wind "naturally" better then 360 rotor??! i realised i did not
need to wind as much even though its the same 40 hr reserve.
so i did a simple experiment with a watch winder and mounted a bumper (open cased and
reversed) and a modern rotor (display case version, reversed mounted)
i noticed because of how limited the angles for bumper , they do a consistent 180-200 degree
ticktock swing. while the modern rotor would sometimes get caught in "suspended animation"
with no winding motion. this is most obvious in directional changes.
when i sped up the rotation to simulate typical human hand movement, with quick directional
changes, the modern rotor were caught in a lot more suspended mode.