New Ultegra RD-6700 problem
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  1. #1
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    New Ultegra RD-6700 problem

    Have a brand new rear derailleur (10) and one of the sealed pulley gears spins freely...the other won't spin at all but does move under light finger pressure. Shimano tech says defect, Bike mechanic says normal...what say you?
    Thanks

  2. #2
    Rub it............
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    Normal.
    You can't fix stupid.

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  3. #3
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    Spinning freely?

    Quote Originally Posted by deloid101
    Have a brand new rear derailleur (10) and one of the sealed pulley gears spins freely...the other won't spin at all but does move under light finger pressure. Shimano tech says defect, Bike mechanic says normal...what say you?
    What do you mean by "spins freely"? The pulleys should turn easily with minimal friction, but they are so light that they don't keep spinning if you give them a flick. If one does, it sounds like maybe there's no lube in it. If you're feeling friction, then that could be as simple as a bent dust cover. It could also be a lack of lube. They're really easy to take apart and inspect, so that should maybe be your next step.

  4. #4
    Cycling induced anoesis
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    The upper guide pulley has rubber seals that create some drag, so it's normal for it not to spin like the lower tension pulley that has no such seals. That said, it should still rotate smoothly, so if it does, I vote 'normal'.

    For reference:
    http://techdocs.shimano.com/media/te...9830672024.pdf

  5. #5
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    Quote Originally Posted by Kerry Irons
    What do you mean by "spins freely"? The pulleys should turn easily with minimal friction, but they are so light that they don't keep spinning if you give them a flick. If one does, it sounds like maybe there's no lube in it. If you're feeling friction, then that could be as simple as a bent dust cover. It could also be a lack of lube. They're really easy to take apart and inspect, so that should maybe be your next step.
    The outer one that acts as a guide always spins freely with a flick of a finger. that I know is normal. The second gear is built with a more robust bearing and this is the one that takes some of the lateral torque when shifting gears. I suspect it's NOT sopposed to spin freely since it's action is different and due to it's light weight the "drag" is insignificant.

    That bearing could be improved but at a higher cost and slight increase in weight.

    I'm still curious what most folks find when installing their new derailleur. I can't imaging putting one in and not testing those little wheels first Don't we all love approaching resistance free motion (except when there is a sudden pile up right in front of you)?

  6. #6
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    sounds normal...they don't spin for long when you give em a flip.

  7. #7
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    Quote Originally Posted by andulong
    sounds normal...they don't spin for long when you give em a flip.
    The lower one spins the uppper doesn't spin on it's own (*after a flick) at all... not even for a nanosecond.

  8. #8
    RoadBikeRider
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    If it is new take it back and compare with another new one. If there is any difference exchange it.

  9. #9
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    But that's too...too logical! There must be a more complex approach-

    Of course you are right and that's what I'll do.

  10. #10
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    Just checked my dura ace & force & what you describe is................normal.

  11. #11
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    Even better than taking it back to the shop. Thanks for checking your dura ace!
    I'm done worrying about this.

  12. #12
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    The top jockey wheels from Shimano run on a ceramic bushing, not bearings. So (especially when new) they tend to not spin as freely as the bottom jockey wheel, which does run in a set of bearings.

    You might check that they aren't dry and add some lube if needed. But I suspect all is actually fine and the top wheel will loosen up a little with use. The top one will never spin as freely as the bottom one. This is by design.

    You'll also see some side play in the wheels, which Shimano does deliberately to allow for minor misalignment and make derailleur adjustment less critical.

    Aftermarket replacement jockey wheels with full ceramic bearings and much less play are available. They work fine, but generally are a little fussier about adjustments. Often these are machined from aluminum, so might run slightly noisier than the Delrin Shimano jockey wheels.

    You really won't notice any difference though, out on the road with either type, except possibly for slightly more noise from the non-OEM pulleys.
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