Ultegra front shifting problems



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?
 
C

Crononauta

Guest
On 19 Jul 2005 12:34:52 -0700, [email protected] <[email protected]> wrote:
> 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).

Hope this help.

--
Massimo Bacilieri AKA Crononauta
Ravenna, Italy
ICQ:4005815