nfmisso

Once upon a time there were no Road or MTB front derailleurs, there were just front derailleurs. Sometime later came Indexed shifting of the front derailleur, and MTB and Road front derailleurs split with slightly different pull ratios. Thus the current state where for indexed Road shifters, you need a Road FD, and for indexed MTB shifters you need a MTB FD. Things are close enough that friction shifters don't care - at least that is my understanding.

Know to the questions:
When did Shimano Road and MTB FDs separate?
Do older ('70s-'80s) Shimano FD have the same pull as newer Road or MTB or something entirely different FDs?

Thank you

Italuminium

Start here for pull, trim etc: All About Front Derailers

1992 is the first listed year for top pull FD's, so I guess that is when the split happened. No idea if the pull was different in that year. Shimano History

And indeed, friction doesn't care what you run. Indexing probably changed the ratio of pull over the years between pure friction FD's and indexed ones, but you'll never need the full pull of a friction lever, no matter what FD you run.

The thing you have to keep in mind is that road derailers generally work well for over 50 chainrings and are designed to take shift over a 13 tooth difference, while triple MTB derailers top out at 48 teeth and shift 10 teeth at a time.

personally, I think a big caged FD looks goofy with smaller rings up front, so either go with a more inconspicuous road fd (like early 90's campy)or a MTB fd if you are going for smaller chainrings, but that's just looks.

nfmisso

Thank you; I had already read Sheldon's article very closely, it does not address when the split occurred, and most importantly if the current road or mtb FD standard matches older derailleurs.