I am asking about 3x9-speed front derailleurs.
The background this time is longer than the question -- I have a Sora based gravel bike and now I try to marry road shifter with MTB front derailleur with almost a success:
front , rear small + big = works small + small = works middle + big = works middle + small = works big + big = works big + small = does NOT work
It means I cannot push cage outwards enough. It is all about some shy 1.5 mm, I cannot believe I am so close to success and yet I see failure. It is not high limit screw on the derailleur, I am simply out of cable pull to shift the cage just a hair further.
So I wonder, what are those cable ratios, are they so minuscule different then they manifest in ~1.5mm of shortage pull? Or could it be that I have to use the same group for the derailleur and crankset (currently I have Alivio and Acera accordingly; for tests I tried not to spend too much money) because such behaviour is not caused by cable pull ratio difference?