Originally Posted by
merziac
Shimano had adapters too and they were/are produced by others.
Yep, only one big bearing, big convoluted theory for it, should come up if you goggle it.
Didn't really stick so they were somewhat short lived.
The idea was to have the foot level with the pedal spindle, which meant the bearings had to be inboard of the platform. Hence the ~1" hole. This also means you use a lower saddle height, the idea being it made you "smaller" to the wind. But I think this puts weird stress on the bearings, so they often failed (so I've read).