those of us who have grown up using friction lever shifting
have learned how to shift a derailleur front mechanism as it works.
you overshift a bit then re adjust the FD cage so as to not touch the chain..
the indexing schemes de-skill that and go clunk into a fixed location..
the adjustments are done on the repair stand, rather than with the hand with each gear change.
IG started twisting the teeth on the hub,
to make the shifting go earlier to get the index stuff to work
and the chains have a bulge in the outer link.
HG they shortened the teeth and reshaped the faces of the teeth
to have ramps and gates to further make the shifting early,
and at the same time create an unsettled chain eager to jump
when the front and the back of the control cable are out of synch.
Last edited by fietsbob; 08-12-12 at 11:09 AM.