Ok, recently I installed a new front derailleur on my Trek 1000 -- it's a Tiagra, to replace the 2203. It seems to be heads and tails above the 2203, but I have an adjustment question.
It (the derailleur) was riding just a little too low on the seat-tube, as when I rode in the middle chainring and applied pressure to the left crank the outside of the derailleur would rub against the teeth on the big chainring. So I moved it up just a hair, shifting into the big chainring is a challenge. If I make a concerted effort to "slam" the brifter (i.e. shift as hard and as far as it can go) it brings the chain into gear, but unless I do that the chain won't move up to the big chainring -- it's as if the derailleur doesn't move out far enough, like it's just a hair too far to the left.
I know there are two screws on the derailleur, but I'm not quite sure how they work. Which one do I turn for the minute adjustment I think I need to make? Can I adjust it out towards the big chainring further without affecting the inside (i.e. small chainring) settings? Is that what I need to do after all, or am I off in left field somewhere?
Any help is appreciated.