I installed a Deore LX crankset (22-32-44 rings) and an LX front derailleur (FD-m571) on a 700c touring type frame (Pake C'mute). There's a big gap between the FD cage and the tops of the chainrings, so I think it should mount lower. (in the current position it requires a lot of trimming in the middle ring.) But if it goes any lower the bottom of the cage bumps into the top of the chainstay.
I picked up this deraillleur used, and i suspect these derailleurs came in 44t max and 48t max versions. How can I tell whether I have the 44t version?
On the back of the derailleur, it says it is for chainstay angles of 66-69 degrees. I pulled out the protractor and found the chainstay angle on this bike to be more like 63 degrees. This makes sense because 700c frames have more bottom bracket drop than 26" frames, and it would explain why the cage interferes with the chainstay. But the 63-66 degree front derailleurs seem hard to find. Where can I find a derailleur that will work better?
If you go to http://bike.shimano.com you can get the chainstay angle specs for all their FDs. (Yes it takes a lot of clicking, but the info is there.) Then you can figure out which models would work best.
If you can't get a hold of the right MTB FD, and you're using friction shifting for the front, a road derailleur will work fine and is almost guaranteed to clear the chainstay.
Spec' Tarmac (road), Ridley Fenix (commuter & fast tourer), Salsa Mamasita (MTB), CoMo Speedster (tandem), Surly Big Dummy (cargo), Airnimal (folder)
The 48-tooth versions of the Shimano MTB FD's have slightly different model numbers than the standard 42/44-tooth versions. I believe the model numbers for the 48-tooth versions end in a 1, but I could be wrong. A little searching through Shimano's Tech Docs should yield the answer.
I just went through a similar problem replacing the FD on my bike. No one listed the OE # including Shimano. I ended up ordering a M412. Then I read on another mail order site that it was only good up to 42 while I have 48 plus they said it was top pull & I needed bottom. So I panicked and ordered a M411 which thier info said was what I needed but what they sent was a M413?? Anyway, I installed the 412 and it works perfectly. Turns out it is top or bottom pull. Very confusing for a newbie like me. I'd recomend the Shimano site for info but it's still a bit confusing for me.