Chain rubbing on the front derailleur

[Becky]

I can use the 50/11 or 34/11 combination on mine, actually all combinations with no problems and no trimming (50/34 in front and 11/34 in back). But I put a triple mountain FD on even though its only a double.

I would venture to say that the triple is what's making the difference. It probably has a wider swing. Even so, I'd be reluctant to use the 34/11 or 12 just because of the extreme chain angle. 50/11 is no problem.

I can use my 34/13 for short periods of time, but not my 34/12 (running a 12-25). It took me a lot of fussing with cable tension to get the trim click in the right place to get the maximum number of usable gears.

[Triskeliongirl]

I do avoid the most extreme positions because it reduces chain life, but my point is that by using a triple FD I can use any combo I want without rubbing and trimming, which is very nice.