Originally Posted by
rccardr
If the clamp has a square shaped shifter mount and 5mm bolt holes, then it will work, assuming the clamp is the correct size for your down tube.
Some of the older shifter clamps, particularly the Shimano ones, have 4.5mm bolt holes that can easily be re-threaded to take a standard 5mm bolt.
...I would repeat the caveat about the diameter of the clamp you buy. If you are putting these shifters on a frame made of French metric tubing diameter, a lot of the stuff you will see for sale used will not fit. If it's Simplex stuff that ws on some other kind of frame, it might. Measure the diameter of your downtube and shop accordingly.