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ultegra chain rub(7 posts)

ultegra chain rubbianchi boy
Sep 28, 2001 10:19 AM
How much chain rub is "normal" with a 9-speed Ultegra group? I've got a 12-27 cassette and 39/53 chainrings on my Bianchi. With the chain in the small chainring, I cannot use my 12,13 and 14 gears without the chain rubbing the big chainring. In other words, I can use only 6 of the 9 gears while in the small ring. This doesn't seem right to me, but my mechanic swears that it's typical for Ultegra. I know you are not supposed to use the small chainring and smallest gear (or the big-big combo), but it seems like you ought to be able to use the 13 and 14 gears without rubbing.

On my other bike, a Gios with Chorus 10-speed, I am able to use all of the gears without significant chain rub while in the small chainring. The Chorus bike also has 39/53 rings but has a 13-29 cassette. I get absolutely no rub all the way down to the 39/14 combination and I don't use the 39/13 because I know you're not supposed to use that combination. The Gios has a shorter wheelbase and chainstays, so it seem it seems like -- if anything -- that would be the bike with the rubbing problem.

Someone suggested that I could solve the Ultegra rubbing by installing a thin spacer, 1-2 mm, between the BB and the right crank, but my mechanic advised me not to do that. He said that would mess up the shifting and alignment. I would like some "second opinions" on this problem.
bad chainlinemtb
Sep 28, 2001 11:17 AM
but regardless, why would you want to use a 13x39 anyway? oh the beauty of the non-indexed front derailleur/shifter!
re: ultegra chain rubthe_gormandizer
Sep 28, 2001 11:41 AM
I had the same problem on my Cannondale CAAD4 when I changed from a triple to a double (also Ultegra, same gears as you). Following advice (from this board) I installed a 1mm aluminum spacer and it fixed the problem.
rub normal with shimanoclub
Sep 29, 2001 6:42 AM
although you should be able to adjust the cable tension so it only rubs in the smallest and/or largest cog. shimano shifters don't have as fine gradations of trim-ability as campy shifters. Ideally you should be able to trim the front cage so it doesn't rub, but shimano's design is faulty. the problem is just as bad with shimano rapidfire shifters. try turning the cable tension barrel so the cage clears the chain on the second and third cogs, then check that it's not now rubbing with the largest cog -- it might be.
Has nothing to do with the front derailleur.nee Spoke Wrench
Sep 29, 2001 5:14 PM
On some bikes, my Klein is one, the chain rubs the big chain ring - not the derailleur cage. I put a spacer behind the bottom bracket and helped it some, but it still rubs in the second smallest cog. I think of it as an audible reminder that it's time to shift into the big chain ring.
Has nothing to do with the front derailleur.Proboscis
Sep 30, 2001 4:46 PM
I have exactly the same problem with my Klein Aeolus triathlon specific frameset. I wonder if it is a Klein specific problem, or with the combination of shimano Dura Ace
Has nothing to do with the front derailleur.dotkaye
Oct 1, 2001 7:20 AM
I have the same problem with:
Shimano Exage crankset
53/38 Werx Avatar chainrings
Trek 2500
At a guess, I'd say it was dependent on the chainrings, crankset, bb, and frame.. so it's not unlikely to occur in a variety of bikes. When I had 53/42 the problem didn't happen, but I can't climb Colorado's hills in 42x23 anymore..