# Noisy jockey wheels



## bernithebiker (Sep 26, 2011)

I seem to be getting quite a bit of noise and vibration from the jockey wheels on my DA 7900 rear derailleur.

I happens in the biggest 4 gears (1,2,3,4). I'm using a DA 23-11 cassette and it's on an S-Works SL4.

Is it right that the top jockey wheel has a fair bit of side to side play, but the bottom one doesn't? (The mech is only a year old, so not worn).

I also removed the B tension screw, as even at minimum, the chain jockey wheel was not all that close to the cog.

Indexing seems to be correct.

Any help appreciated!


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## wim (Feb 28, 2005)

If the derailleur is brand new, a small amount of noise noise and vibration is normal. Once the jockey wheels have some miles on them, things will quieten down. As with all Shimano rear derailleurs, the top jockey wheel is designed to have a good amount of lateral play. Shimano does not specify jockey wheel-to-sprocket distance. They merely tell you to "adjust the guide pulley as close to the sprocket as possible."

Not much concrete advice here. But with noise and vibration being a matter of degree and sensitivity to it (I never hear those things on my own bike), it's about all I can do.


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## looigi (Nov 24, 2010)

The top jockey wheel on Shimano RDs are designed to have lateral play so this is normal. Are they well lubricated and rotating freely? You should have about 6mm clearance between the top jockey wheel teeth and the teeth of the largest cog. Is your chain in good shape?


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## bernithebiker (Sep 26, 2011)

Yes, almost new, so well lubed and spin freely with the chain off, I checked. 

Not less than 6mm clearance, it's about 6 - 10mm. 

Chain, just cleaned it, not old.

I'm thinking it must be an indexing issue, but the derailleur cage looks perfectly lined up with each gear.......hmmmmm!


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## ultraman6970 (Aug 1, 2010)

Some chains are quieter than other ones, in general KMC chains are silent, but since u have a problem with one cog wonder if its a index problem, friction problem or a chain that is too old.

Jockey wheels when get old get noisy too. No idea if DA cassettes use spacers between the cogs, but have seen in campagnolo that guys put the spacers in the wrong place then the indexing goes to hell. Easy to verify if that cassette was disassembled at some point in life.

I would change the chain for a KMC if i was you.


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## wim (Feb 28, 2005)

ultraman6970 said:


> since u have a problem with one cog wonder if its a index problem, friction problem or a chain that is too old


According to the OP, the problem happens in the "biggest 4 gears (1,2,3,4)". If he means the four cogs with the largest number of teeth, noise could indeed be louder in those than in the smaller cogs because of the increased chain tension. I dunno—it all sounds kind of normal to me. Perhaps it's loud only in comparison with an older, well-worn in setup?


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## ultraman6970 (Aug 1, 2010)

Shimano people always cry when stuff doesnt work as intended hehehe


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## savagemann (Dec 17, 2011)

Usually when the drivetrain shifts smoothly through the first range of the cassette, then becomes noisy towards the larger cogs, it is most often due to the derailleur hanger being misaligned.
If you haven't changed the limit screws, i would have a shop verify alignment if you don't have the park dag tool.
Also, how old are your cables/housings?


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## wim (Feb 28, 2005)

ultraman6970 said:


> Shimano people always cry when stuff doesnt work as intended hehehe


Well, perhaps. But a misunderstanding of "as intended" is the often the problem. Take the supposed 6 mm or so clearance between jockey wheel and cog: there's no such specification in the Shimano technical document for this derailleur. So people often drive themselves crazy chasing down non-existing problems.


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## DrSmile (Jul 22, 2006)

I agree you should check the derailleur alignment. The Park tool works fantastic for this. I did once have a very small string get wrapped around the jockey wheel shaft which kept it from moving sideways. I wasn't able to see it until I took the side plates off the derailleur and disassembled it.


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