Hello All:
I wanted to set up a bike with Campy 9s Ergo shifters and derailleur to work with a Shimano 9s cassette. I have a bike set up like this already using the Shiftmate but I wanted to see if I could make it work without spending another $60 or so.
Sheldon Brown's (RiP) website provides a wealth of information. First his cassette spacing crib sheet includes the distance between cogs: 4.55mm for Campy 9 and 4.34mm for Shimano 9s, a difference of about 5%.
Next, he shows that alternative cable routing can be used to alter the distance traveled with each gear change. I needed to decrease the travel for each click by 5% which means I need to move the cable 5% further away from the pivot. He shows this example:
.
In looking at my 9s derailleur I measured that the distance from the pivot to where the point where the cable normally pulls to be 35.57mm.
By wrapping the cable around the pinch I was able to increase that to 37.46mm, an increase of 5.3%.
The results, at least for this proof of concept test were really good. I've done my best to show with the pics that the pulley is perfectly lined up on the small and the large cog but it was hard to get the camera angle just right.
Will set this up on a bike and take it for a ride this weekend.
Cheers,
Jim