Without boring you all to tears, it is very technical.
Shimano (did I just type that?
) rear mechs pull a cable ratio of 58%, or if the cable is routed around the opposite side of the cable clamp, 64%. Pre 2000 campag was 70% and post 2000 67%. SRAM 100%, although in tests, it was measured at 90&.
The shifters also pull a diffeent amount of cable for each click - Shimano (again
) 8, 2.78mm, 9 - 2.52mm, campag 9 3.05mm and 10 2.78mm.
If you do the math, you can work out that per shift, a shimano (!) 8 lever with a campag rear mech pulls 4.16mm per click, and campag 10 speed 4.15mm, which is so close as to be perfect.
OK
I'm off to do some yoga
On the importance of guru, Nanak says: Let no man in the world live in delusion. Without a Guru none can cross over to the other shore.