Originally Posted by
Chrome Molly
I spent last evening tweaking the height of the derailleur and have it about optimized (given the tradeoff between height above the rings and probability of chain drop). It is up higher than the mfr suggested. I had several small to big ring shifts in today's ride, in relative anger, with no chain drops. The FD still rubs on the 29 cog, but in a less annoying fashion. The rub is from the chain riding the top of the chainring until settling in (a product of the cross chaining). It rubs more "off power" than "on" so maybe this will improve as the rings wear in a little. At the mfr height, it rubbed a little on the next smaller cog, and it doesn't do that anymore as it's set now.
I would like a FD with more clearance, so I may try an old rival unit that I have around. But if things stay as it is, I may not mess with it further.
Wait, you are in the 29 and small ring, then shift to the big ring ?!?!?
That's rubbing the cage while the chain is trying to shift to the big ring ??
Don't do that, shift the rear out of the 29 a few gears (25, 23 ...). Then shift to the big ring if you need to when you have more speed, and there will be less load on the FD and chain.