Originally Posted by Milton Keynes

That's an interesting design. The one I remember (as best I can remember) came with a bracket that mounted on the drive side of the rear wheel, and likely operated on a similar principle. But, as I said, that was around 25 years ago, I've slept since then, and I didn't look at it closely enough to figure out how it worked when I did see it.

I still say there's nothing wrong with manual shifting that requires an automatic shifter. I can imagine if it were a $19.95 "as seen on TV" product the commercials would have all us cyclists in black & white struggling like crazy to shift gears on our bikes.

I don't understand why that page called centrifugal force "mythical," though, since it is very much real.