Campy SR rear derailleur alignment ?
04-02-22, 08:55 PM
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Campy SR rear derailleur alignment ?
I have been trying to get my recent build set up, but having some trouble with the rear derailleur, which is a `82 Campy Super Record. This is on a Raleigh Team 753 bike with a brand new freewheel. Here is how it looks pretty much across the cluster:
As you can see, the chain wants to consistently skip to the outside of the bottom pulley. To control for variables, I have tried it with a different chain, as well as a different derailleur (Nuovo Record), it seems to consistently do this. I did a quick check with a derailleur alignment gauge, and it seemed close enough, but now I am wondering if that might be it. This is a frame that was recently repaired (chain stay replaced), so wondering if the derailleur hanger is out? Any thoughts would be appreciated....
Thanks,
Andy
As you can see, the chain wants to consistently skip to the outside of the bottom pulley. To control for variables, I have tried it with a different chain, as well as a different derailleur (Nuovo Record), it seems to consistently do this. I did a quick check with a derailleur alignment gauge, and it seemed close enough, but now I am wondering if that might be it. This is a frame that was recently repaired (chain stay replaced), so wondering if the derailleur hanger is out? Any thoughts would be appreciated....
Thanks,
Andy
04-02-22, 09:39 PM
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Are you willing to sub a non Campy part onto your bike? Try a different brand pulley. Another possible solution is to use a file to bevel the pulley teeth on one side.
Campy NR era pulleys don't have much tooth height and with current chains and their reduced side plate dimensions the pulley teeth and chain links don't have much engagement overlap. So the chain more easily rides up and over the teeth with the cage side plate being the limit. I'll bet this only happens on some of the more chain angled combos. The cage alignment can sometimes be the big reason. If the cage isn't aligned WRT the length of the bike axis it will worsen the chain ride up. Depending on the ft and back chain lines, the chain stay length, the cog set width, the chain design, the pullet teeth shape and the der cage alignment (in all 3 axis) this ride up can be more or less. Andy
Campy NR era pulleys don't have much tooth height and with current chains and their reduced side plate dimensions the pulley teeth and chain links don't have much engagement overlap. So the chain more easily rides up and over the teeth with the cage side plate being the limit. I'll bet this only happens on some of the more chain angled combos. The cage alignment can sometimes be the big reason. If the cage isn't aligned WRT the length of the bike axis it will worsen the chain ride up. Depending on the ft and back chain lines, the chain stay length, the cog set width, the chain design, the pullet teeth shape and the der cage alignment (in all 3 axis) this ride up can be more or less. Andy
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AndrewRStewart
AndrewRStewart
04-03-22, 03:49 AM
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I have seen this many times with rear derailleurs that are damaged. Usually it is cage alignment where the jockey wheels are not in the same plane or the wheels are out of plane with the rest of the drive train. Recheck hanger alignment as well. Andy's suggestion of changing jockey wheels may help.
04-03-22, 06:03 AM
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thanks guys, I will try some new non-Campy pulleys
04-03-22, 08:07 PM
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From here in the cheap seats I am with T-habs, the hanger is bent inward so check the alignment of the hanger. Smiles, MH
