Originally Posted by
Doctor Who
I did this to my Paramount PDG Series 3, which came stock with 7-speed Shimano RX100. I replaced the freehub on the original RX100 hub with an 8-speed unit, and then added a 12-tooth cog. The downtube shifter was replaced with a Ultegra 600 brake/shift-lever. Nothing else was done and it works pretty well.
Did something similar with my ca. 1992 Peugeot, which was seven speed RX100. How have 9 speed Tiagra shifters, 105 RD, FD, Cassette, & Chain. Needed a new rear wheel so I just got a pair of 550s cheap. Also new BB because it was getting a bit rough. Still have the same cranks and brakes.