I am having a very difficult time getting rub-free front shifting, even with trim. The derailleur is straight, and, as far as I can tell the limits are set correctly. The height also seems good, i.e. allowing for a gap of a mm or two between the FD and the big chain ring. I have a 53-39 double in front and 12-27 in back. I just replaced an ever-so-slightly bent large chain ring with one that is clearly straight. The problem seems to be mostly in the big to middle combinations, i.e. the 53x15, 17, 19. No matter how I adjust the cable tension--which is slightly tricky in my case because I do not have a barrel adjuster--at least one of these middle gears seems to rub. If I feather in one direction, the chain will rub on the inner plate of the FD, and if I feather the other way, the chain will rub on the outer plate. This predicament is compounded by the fact that my frame seems to have a somewhat flexy bottom bracket area.
Are the tolerances of Ultegra FD's really this fine? I was looking at the FD of an earlier vintage of Ultegra that I have on another bike and it seems quite a bit more forgiving, i.e. it is less shaped and the distance between the inner and outer plates seems less wide. At this point, I would gladly sacrifice crispness of shifting to get rid of rubbing. Any suggestions?
I am having a very difficult time getting rub-free front shifting, even with trim. The derailleur is straight, and, as far as I can tell the limits are set correctly.
Hallo.
Try aligning FD with CHAIN, not chainring, when chain is on 53/12. I made like this and discovered I could set FD outer limit inner than aligning FD with chainring: it worked so well for me that I have no need to trim at all using biggest chainring from 3rd to 9th rear gear, and smaller chainring from 1st to 7th rear gear (with Ultegra 2003 9s).
