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Chain rub?(8 posts)

Chain rub?Zira
Sep 6, 2001 12:26 PM
Hey all,
I just switched over from a triple to a double(chorus 10 spd). I've noticed that when I'm on the small ring and smallest two cogs the chain rubs up against the chianring, at least I think it's the chainring. Is this what is meant by chain rub? And, is this normal? It didn't happen with the triple, at least not in the 42 which is what is used most of time. Thanks.
re: Chain rub?novagator
Sep 6, 2001 12:34 PM
It may be rubbing against your derailer. I sometimes have that problem with my Shimano Ultegra componants. As with the Shimano, Campy shifters allow you to "trim" up the derailer by gently feathering the front derailer shifter up a notch, thus moving your derailer out enough so that your chain doensn't rub.
re: Chain rub?Mel Erickson
Sep 6, 2001 1:03 PM
More than likely rubbing your front derailleur cage. Riding in the small/small is not advised, too much wear on the chain and cogs. Plus, there's really no reason to use these combos because they are duplicated by others using the big chain ring and your chain line is much better. You can trim your derailler to eliminate rub. If it's really rubbing your big chain ring then I would check your BB axle length since you switched from a triple to a double. Did you switch axles? Have the LBS check this out.
not uncommon with 10 speed...C-40
Sep 6, 2001 1:51 PM
First of all you shouldn't use the little ring and the smallest cog with any double crank, be it 8, 9 or 10 speed. The extreme angle is hard on the drivetrain.

If trimming the left ergo lever up one click doesn't stop the noise, it's the chain rubbing against the big ring. This is not uncommon, since the 10 speed big ring is spaced closer to the little ring (than 9 speed). I get a very slight rub when using the small ring and second cog, so I use it only briefly. It's the only small disappointment that I've experienced with the 10 speed drivetrain. As long as you are using a Campy 102mm spindle bottom bracket, standard on Chorus and Record, there's probably nothing wrong.
not uncommon with 10 speed...mackgoo
Sep 6, 2001 2:26 PM
I take issue with the not uncommon. I just put on the Record 10sp. I can go from one end to the other on either chain ring and I get no ring rub, you do have to trim the der. 1 click of course. As was said this is not a good way to run the drive train for long. But if it is on short hill I get lazy and just go all the way over VS doing what I should do and step down on the chain ring, my only complaint is once I've crested the hill do you how long 9 clicks seems? seems like it takes for ever:-> you should check your B/B though, make sure everything is tight.
Maybe yours doesn't, but it's still commonKerry Irons
Sep 6, 2001 5:38 PM
It has to do with chainstay length, how firmly the crank is pressed on the BB axle, gear sizes, etc. It is not something that you can "adjust" out of the system with "proper" set up. If your chain line is such that in the small-small combo, the chain rubs the big ring, then that's it. And it is fairly common. Go to any bike rally or race, and start inspecting the inner face of the big chainring on people's bikes - you'll see chain rub marks quite freqently (probably the majority of cases, perhaps 80-90% of cases).
Maybe yours doesn't, but it's still commonLarry Meade
Sep 7, 2001 4:59 AM
Agreed. The shorter chainstays on many of today's bikes have made this a common occurance. Nothing to really worry about there usually other gear combos that will nearly duplicate the small/small combination.
Maybe yours doesn't, but it's still commonmackgoo
Sep 7, 2001 2:06 PM
You know I checked today, infact I do get a small amount of rub against the big ring when on the small and small. It's just this is a combo I'm never in, I get lazy and stay on the big ring and on ocassion may go all the way over to the largest cog. But whenever I am on the small chain ring I'm always going to the big ring when I get thru about half the cassette.