Originally Posted by
Steve B.
Biggest issue is can you raise the front derailer ?.
You’ve got a mt. bike sized crank, so the front derailer is sized and positioned for that large (42) chainring size. If you’ve got a brazed-on derailer hanger (can’t tell from the photos), raising can be an issue. A clamp on derailer can be readily raised to the limit established by the water bottle bosses.
It turns out I have a Shimano FD-M610 which is a clamp-on. Interestingly, it's 3-ring capable but at this point I think I'm sticking with a bigger 2 ring. Specs say that it's max ring size is 42T (what I'm running right now) but you're saying I can just raise it and it'll be fine for a 48T?
Originally Posted by
cpach
Also check out your shifter--is there a small switch on the underside? It may be a 3x compatible shifter as is, as they'll work with a double FD. If so you can get a 3x crank and derailleur.
No switch on the shifter unless it's supremely hidden, but I think I'm going to stick with a bigger 2 ring anyway. Interestingly, I found (above) that my front derailleur is 3-ring capable even if the shifters aren't.
Originally Posted by
nfmisso
with a suggested 48/34 (14T difference).. Front derailleurs are sensitive to the difference in the number of teeth between adjacent chain rings.
Once I got the specs on my FD it looks like it's got an 18T difference - I'm presuming that's larger than what you expected since it's actually 3-ring capable. I'm still expecting to be in the 14T range, but I'm assuming that 18T limit is still the same regardless of whether I'm running a 3ring or a 2ring, right?