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Unusual noise in new drivetrain

lochussielochussie Posts: 276
edited November 2012 in MTB workshop & tech
I've just fitted some 10 speed stuff: SLX shifter, cassette and clutch mech and SRAM PC1031 chain. The gears work fine but there is a distinct whirring noise, seems to be coming from the lower jockey wheel. Holding finger to this I can "feel the noise" too. As if the chain isn't meshing with the wheel properly, but no skipping at all. Noise is there in all font and rear combinations. After 20 mins tuning on workstand there were little bits of worn off jockey wheel, but maybe this is normal. Any ideas, or is this just standard for this mech? Does the chain have to be put on in a certain orientation?


  • nicklousenicklouse Posts: 50,675 Lives Here
    make sure it is seated correctly.

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  • JonnyNJonnyN Posts: 181
    Have you routed the chain on the correct side of the metal tab between the jockey wheels?
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  • Chain is routed correctly. Brand new stuff. Looking at the fit of the chain on the jockey wheel, it doesn't seem great. Eg, wrapping a 3x inner+outer plate section of chain around half the wheel, the section is too long and won't sit snugly on all the teeth. Maybe this is normal though, I've never looked closely before. If I didn't know better I'd say the pin-pin distance of the chain is too long for the mech. But as far as I know SRAM chain + Shimano mech is still fine in 10 speed.

    I don't know if it's related but when the cranks are turned there is a faint clunking feeling a few times per rev. Coming from the chain or rear gearing as not there when done with no chain on, plus BB is new. The crankset, rings and front mech are still 9 speed but work fine apart from the above.

    Might try a Shimano chain tomorrow.
  • Post a pic up or even better a link to a vid.
  • cooldadcooldad Posts: 32,599
    Maybe a pic would help. You lost me.
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  • Here's a vid: ... tif_t=like

    All it really gets across is the whirring noise, might be quiet in vid but is really pretty loud. There is a bit of rub from a bent rotor in the background.
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