FD and cransket compatibility issue ?
greetings: this may appear somewhere in this forum, but going for it here just the same....
with a recently acquired used bike, i have been having issues with front derailleur shifting. the bike has a Tiagra 52-42-30 crankset and a Shimano XTR triple front derailleur. major problem is shifting from the middle (42t) ring to the big (52t). the bottom of the inner cage rubs against the teeth of the 42t. tried tweaking the height of the FD, but just can't seem to get the shifting to be right. made all necessary adjustments to limit screws, etc.
so, my research on this seems to point to the FD not being compatible with this crankset in that the FD is designed for a 50T max ring, and i think a 12t minimum delta is required between the large and middle ring. would you guys concur with that assessment ?
another question: with a 50-39-30 crankset: how much smaller of a granny gear can i go ?
thanks for any thoughts on these....