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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?
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?