Transmission in the BB
 

This is interesting stuff: http://www.schlumpf.ch/innovationse.html

Sheldon posted a reference, and thinking it looked familiar, I checked. Sure enough, I just read about something similar in The Dancing Chain (a great book!). There were similar things made by Variand and Tilhet in the period of around 1895 to 1905.

What goes around comes around. So to speak. :rolleyes:

Cheers...Gary

In the 1930s, Adler ("Eagle"; Germany) sold bikes with 3-speed sliding-gear transmissions built into an oversize bottom bracket.

I think Schlumpf really missed marketing bet by not supporting fixed-gear applications, for which this would be ideal.