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rear derailleur pully replacement, why do it?(7 posts)

rear derailleur pully replacement, why do it?rtyszko
Aug 5, 2002 8:51 AM
Is there really a reason to replace the pullies? My gruppo is about 5 years old with lots of miles. I took apart the rear derailleur cage yesterday to fully clean the pully assembly and it got me to thinking that maybe I should change the pullies. I don't notice any performance problems or any additional noise, so why would I change them? Is there a wear and tear issue (like the cogs/chin rings?) that I should be aware of?

BT
There was a study a few years ago...cory
Aug 5, 2002 10:22 AM
It was sponsored by one of the companies that makes aftermarket pullies, I think, but they claimed that the reduced friction from THEIR pullies was good for a measureable lead in a time trial. I've forgotten the number--"the equivalent of climbing a 25-foot hill at the finish," or something like that.
FWIW, I swapped mine one time when I had a gift certificate from Performance and didn't need anything else, and I couldn't feel any difference. It shifted the same, and I never did win any time trials. As for wear, I think the rest of the driveline would show it before the pullies, which are essentially idlers--there's not much stress on them.
re: rear derailleur pully replacement, why do it?JimP
Aug 5, 2002 10:49 AM
I have been known to be a little obsessive about keeping the driveline clean. I do clean the chain with naptha in a "chain-box" and lube with a hot wax. I also clean the other parts with naptha and a brush. The jockeywheels are part of the driveline that I have looked at in the past as a point of resistance. The older and cheaper components had sleeve bearings that would get dirty and create drag very quickly after cleaning and re-lubing. The newer and more expensive components do use ball bearings but they are very small and difficult to clean and re-lube. I prefer the sealed type of bearing used by Carmichael. These bearings can be opened by carefully prying up the seal and cleaning if necessary followed by refilling the bearing with fresh oil and then pressing the seal back into place. These jockey wheels may be a little noisier since they are machined aluminum but they feel like they have less drag than even the newest DA ball bearing jockey wheels.
re: rear derailleur pully replacement, why do it?Jofa
Aug 5, 2002 12:53 PM
The problem with this obsessiveness, though it may be satisfying, is that it is not the best attitude for your bicycle. Your chain, like your dog, would rather be mucky and healthy, than ascetic and restrained. The difference in total drag between different kinds of jockey wheel bearings is vanishingly small, and entirely undetectable to the rider, unless the sensitive soul is also troubled by that pea 'neath his mattresses. Component designers use plain bushes here for the admirable reasons that they are durable and cheap.

Jofa
Not CarmichaelKerry
Aug 5, 2002 5:14 PM
Carmichael pulleys have a general reputation for poor durability, though some love them. Aftermarket pulleys in general do not fare well in the eyes of most. Absent riding a lot in the rain, pulleys should only need a clean/lube once per year. Campy Record uses bushings - "older and cheaper?" Campy C-Record used bearings, but they were quite easy to clean and lube. Though Carmichael pulleys may "feel like they have less drag" there is no data to support that in actual use.
Okay so I cleaned them. Anything else to do?rtyszko
Aug 5, 2002 7:47 PM
So I took the cage apart and cleaned and degreased the snot out of the two pulleys and then re-lubed them. If what I'm hearing is correct, then despite having 20K miles on them, they are still okay? I really don't have to have new shiny Carmichael pulleys?

BT
My pulleys have 42K miles (nm)Kerry
Aug 6, 2002 4:43 PM