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Thread: ghost shifting

  1. #1
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    New question here. ghost shifting

    Hey everyone,

    I have been having a problem with ghost shifting lately. It seems to happen only when I am in the biggest gear on the rear cassette under torque. I noticed that the "free-hub body" (the part on the wheel that the cassette threads onto) has a lot of play in it. Does anyone think that this could be causing the problem? All other things seem to be in order. The whole drive train has less than 100miles on it.

    Thanks,

    Jeremy

  2. #2
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    Quote Originally Posted by AZinSC
    Hey everyone,

    I have been having a problem with ghost shifting lately. It seems to happen only when I am in the biggest gear on the rear cassette under torque. I noticed that the "free-hub body" (the part on the wheel that the cassette threads onto) has a lot of play in it. Does anyone think that this could be causing the problem? All other things seem to be in order. The whole drive train has less than 100miles on it.
    What brand / model of hub do you have?

    Does the cassette actually slide back and forth? Or does it have a bit of a wobble when backpedaling the chain?

    If it's actually sliding back and forth, make sure that the cassette lockring is tight. If the cassette appears to have a slight wobble, this might well be normal. (It's not exactly desirable, but seems to be harmless so long as the wobble isn't too great.)

    Also check the low limit screw adjustment on the rear derailleur and make sure that the derailleur hanger is not bent. (My money's on the low limit screw adjustment. But I'll switch my bet to the derailleur hanger if you've fallen recently and the bike landed on the drive side.)

  3. #3
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    Thanks for the advice,

    Some more info:

    the wheel is a mavic crossride. shimano cassette. No lateral play. The lower limit screw has been adjusted; I still had the problem afterwards. The wobble just seems excessive compared to all my buddies bikes. I thought about the hanger but I can't remember any crash that corresponds with the problems. I might have to have a shop but the bike up on the stand and take a look at the alignment of the hander. I mentioned that when I had a shop take a look at it. They did not seem to think it was an issue.

  4. #4
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    try unscrewing the barrel adjuster on the deraillier or shifter 1/4 to 1/2 a turn. since you have only 100 miles on the drivetrain (cables too, I'm assuming) the cables may have stretched a bit
    the limit screws shouldnt have anything to do with ghost shifting, they "limit" the travel of the deraillier

  5. #5
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    Quote Originally Posted by dan0
    tthe limit screws shouldnt have anything to do with ghost shifting, they "limit" the travel of the deraillier
    AZinSC said that ghost shifting is only happening in the biggest gear. If the limit screw were adjusted such that the derailleur can't quite line up with the biggest gear, then that could easily cause ghost shifting, particularly when coupled with a wobbly cassette.

    AZinSC: Unscrew the low limit screw about half a turn and see if that fixes the ghost shifting.

  6. #6
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    Quote Originally Posted by KevinB
    AZinSC said that ghost shifting is only happening in the biggest gear. If the limit screw were adjusted such that the derailleur can't quite line up with the biggest gear, then that could easily cause ghost shifting, particularly when coupled with a wobbly cassette.

    AZinSC: Unscrew the low limit screw about half a turn and see if that fixes the ghost shifting.

    edit
    just noticed you have a mavic hub, how old and was it ever serviced?
    if you dont re lube mavic hubs every once in a while the rubber seal gets dried out and wears away the plastic part of the freewheel body. sounds like excactly what happened. when it wears the hub starts moving back and forth enough to shift
    new freewheel body $40, seal $8 hopefully you didnt ruin the hub itself

    HTTP://www.elviskennedy.com/page10/page10.html

    check out figure 6 the hub has a light yellow plastic liner
    figure 8 is the seal that rides on the plastic
    Last edited by dan0; 11-02-2007 at 09:23 PM.

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    Thanks for the feedback everyone. Dan0, I think you are probably right about the hub. It has not been lubed or maintained. All the other study limit adjustment, barrel adjustments, help but do not fix the problem. I can't adjust the set screw enough to prevent the ghost shifting without losing the biggest cog.

    J

  8. #8
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    Quote Originally Posted by AZinSC
    Thanks for the feedback everyone. Dan0, I think you are probably right about the hub. It has not been lubed or maintained. All the other study limit adjustment, barrel adjustments, help but do not fix the problem. I can't adjust the set screw enough to prevent the ghost shifting without losing the biggest cog.

    J
    well, when I saw Mavic I remembered what happened to me, I snapped a piece of the pawl off, when I cleaned out the hub I didnt lube the rubber seal, rode it for 2 weeks while waiting for the parts, seemed Ok, but started shifting by itself, I put off checking because I was going to rebuild anyway, bad move, when I took it apart the rubber seal had worn into the plastic, causing it to move back and forth. thats how I know how much the parts cost. the labor is real easy, just follow the guide I posted and now I take it apart and relube about twice a year

  9. #9
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    Ghost shifting can also happen with a dual suspension setup when the rear triangle moves. I had a Stumpjumper fsr that would ghost shift when I changed shifter cables and didn't provide a large enough loop of cable housing between the bottom bracket and right chain stay.

  10. #10
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    One other thought, if everything else looks to be adjusted properly, look at the actually cassette. I had a similar problem and adjusted everything perfectly but as soon as I pushed up a hill it would ghost shift. Finally I looked at the cassette and it was bent. Not sure when or how but a new cassette and no more ghost shifting. Just a thought.

  11. #11
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    I've had trouble with SRAM 991 chains (on SRAM clusters). They seem to like getting stiff links even from brand new and have given me the worst ghost shifting/slippage trouble Ive ever known. Don't know what you're using, but on MTBR they are one of the most reviewed and worst rated products. I've used Sachs, Sedis, SRAM chains for years, but the latest ones have caused me nothing but grief and I've bailed out to Shimano.

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