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  1. #1
    Silence and Thunder...
    Reputation: xjbebop's Avatar
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    Ghost shifting solution?

    been searching and reading till my eyeballs wanna bleed.....

    Has anyone found a foolproof solution for ghost shifting?
    You know, when everything checks out mechanically sound, but the rear jumps gears occasionally when under torque and the trail is bumpin'...
    ...every day sends future to past...

  2. #2
    No, that's not phonetic
    Reputation: tscheezy's Avatar
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    Use Sram.
    My video techniques can be found in this thread.

  3. #3
    Lay off the Levers
    Reputation: Bikezilla's Avatar
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    Some things if you haven't tried them yet:
    1) New cables and housings all around
    2) Doublecheck the seatstay housing loop length. It's a primary cause of ghost shifting under compression. If it's too long when it doubles over it'll pull the cable just enough to jump a gear...especially on the hyper sensitive Shimano 2:1 setup.
    3) Make certain your Der hanger is dead-on straight. If it's bent some when you tweak the shifting enough to compensate you could make the bike more sensitive to ghost shifting caused by reason #2.
    4) Try a different der. Shimanos can get more sensitive over time. My XTR did and it drove me nuts.
    5) What Tscheezy said. SRAM goes a long way to fixing a ton of chronic problems. I've had both on two different bikes now, I'm convinced.
    Faster is better, even when it's not.

  4. #4
    Living the Dream
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    Ditto

    Quote Originally Posted by tscheezy
    Use Sram.
    Haven't ghost shifted since switching almost 3 years ago.
    "And I shout that your all fakes and you should have seen the look on your face"

  5. #5
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    Reputation: 29Colossus's Avatar
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    Single Speed

  6. #6
    Lay off the Levers
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    Quote Originally Posted by 29Colossus
    Single Speed
    Would sombody PLEASE close that door?!??!!


    Faster is better, even when it's not.

  7. #7
    Silence and Thunder...
    Reputation: xjbebop's Avatar
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    I run sram rear der's & shifters. New housings & cables, everything lightly lubed. The hanger looks perfect w/ a straightedge and eyeballs parallel w/ the chainrings. But...??
    I'm wondering if something is out of alignment or if I'm missing something in my adjustments. I usually have no problems w/ setup.
    This only happens on occassion under certain circumstances as noted...
    I've seen other bikes do the same thing and was wondering if anyone's isolated the cause...
    ...every day sends future to past...

  8. #8
    Silence and Thunder...
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    Quote Originally Posted by 29Colossus
    Single Speed
    very tempting, but my old tequila-soaked body likes gears, thank you...
    ...every day sends future to past...

  9. #9
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    Quote Originally Posted by Bikezilla
    Would sombody PLEASE close that door?!??!!


    Okay, okay... just go with the SRAM solution.


  10. #10
    Lay off the Levers
    Reputation: Bikezilla's Avatar
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    If you don't have a DAG, change the hanger anyway just to eliminate that variable. Maybe some bent cogs on the cassette? Can you change that too to test it out?
    Did you check the TT/ST housing length? A little long really can cause ghost shifting.
    Faster is better, even when it's not.

  11. #11
    ... I guess you won't be
    Reputation: jokermtb's Avatar
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    Not sure if you already discounted this option, but I've seen cases where someone has used cable housing that is for 4mm derailleur cables, and then used a standard 5mm cable....this will definitely work fine when conditions are perfect [like in a workstand], but throw in a touch of dirt, moisture, etc. and it all goes to hell....

    try running your rear deralleur cable outside of the "taco" instead of underneath + through it...it may need to move more freely when the suspension is compressing/rebounding...
    Yes, we do indeed rock...http://www.myspace.com/spokedrunkies

  12. #12
    Silence and Thunder...
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    thanks guys. hopefully I'll get time this weekend to experiment some more.
    I'll report any positive findings.
    ...every day sends future to past...

  13. #13
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    Reputation: techFiend's Avatar
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    check rear hub freewheel for play. with the rear wheel off the bike, lay it on the ground with the cassette facing upwards. assume that the Z-axis is parallel to the axle (perpendicular to surface of ground). grab the casette in your hand and try to rock it around the X or Y axes.. You will feel the play if it exists. If excessive, this play can cause gears to skip when you apply mucho torque to the gears.

    i had this on me M965 hubs. a wee bit of adjustment and it was back to no skip. i don't know if such adjustment exists in other "sealed bearing" hubs...

  14. #14
    Brass Nipples!
    Reputation: Bob the Wheelbuilder's Avatar
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    Quote Originally Posted by techFiend
    check rear hub freewheel for play. with the rear wheel off the bike, lay it on the ground with the cassette facing upwards. assume that the Z-axis is parallel to the axle (perpendicular to surface of ground). grab the casette in your hand and try to rock it around the X or Y axes.. You will feel the play if it exists. If excessive, this play can cause gears to skip when you apply mucho torque to the gears.

    i had this on me M965 hubs. a wee bit of adjustment and it was back to no skip. i don't know if such adjustment exists in other "sealed bearing" hubs...
    The cassette itself can be loose too. Some new ones won't tighten up properly without a miniscule spacer to the inside.

    Also try the method described for Shimanos (but it works for SRAM): shift to the next to the smallest cog. Use the barrel aduster to tighten the cable while turning the cranks until the drivetrain just starts to make noise as it tries to climb to the next biggest cog, then back off slightly until things quiet down again.
    {Principal Skinner} Hmm. Whoever did this is in very deep trouble.
    {Martin} And a sloppy speller too. The preferred spelling of 'wiener' is w - i - e - n - e - r, although 'e - i' is an acceptable ethnic variant.

  15. #15
    jrm
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    Full housing...

    long enough to allow the cable to move at the stops/bends as the suspension is moving..
    Wreck the malls with cows on Harleys

  16. #16
    Anytime. Anywhere.
    Reputation: Travis Bickle's Avatar
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    Quote Originally Posted by jrm
    long enough to allow the cable to move at the stops/bends as the suspension is moving..

    2nd the full length housing. Read about here on the old MTBR about 8 years ago and it cured the ghost shifting on my RM Element. I've always used full length for the rear since.
    I got some bad ideas in my head.

  17. #17
    Silence and Thunder...
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    funny, I tried/checked all of those things, even the full length housing.
    Both of my sram-turners had done this to me just a few times since i got 'em.
    *level singletrack, very bumpy, seated cranking on the pedals, ghost shift (not chain skip) in the smaller cassette cogs...

    bothersome, but i didn't worry about it too much.
    Then, I just recently changed out my XO long cage for a new 07 X9 med cage on the spot because I had put a med cage XO on the flux and really like it. 07 X9 triggers too.
    I had a lot of problems getting the new der to work right. went thru all the replacement parts, etc...
    So I put the XO back on and started over, still with less than perfect shifting. That's when I started this post to see what I might learn. Wondered if someone had singled out the cause/cure for ghosting...

    Rode this morning w/ a large group of friends. The chain jumped a few times at the start, so I gave the barrel a few more twists. Shifter perfect the rest of the day. I even pushed on it a few times in the * conditions...no problem!
    I'm not gonna consider it 100% until 5-10 more rides w/ no problems....we'll see.
    Appearantly, at this point I just didn't have the cable adjusted properly from either new housing settling in and/or stretch.
    I also wonder if the new X9 der has a problem or if it was just me. I'll try it out again after I'm happy w/ the XO.

    oh yeah, OT- actually saw a juvenile puma yesterday!
    I'll start a new post w/ my crappy picture later...

    THANKS FOLKS!
    ...every day sends future to past...

  18. #18
    Lay off the Levers
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    Cables housing settling into the ferrules and ferrules settling into stops can really screw up a new build. It'll be fine on the workstand and slowly but surely shift worse as repeated shifting tension forces the housings and ferrules into a solid resting place. Usually a few turns on the barrel will take up the slack and resolve the problem.

    But I've never seen it cause ghost shifting. This usually happens when extra tension is put on the cable during travel which pulls the der up towards the next cog. Housing settling into the ferrules or the ferrules settling into the cable stops would add slack which is the exact opposite of what usually causes compression ghost shifting.
    Faster is better, even when it's not.

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