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  1. #1
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    Xtr phantom shift

    04 or 05 xtr 9spd on a epic comp. me 200 lbs in good shape, when mashing on pedals in middle gears get phantom shifting. Just keeps shifting tell I back pressure off and it settles in on gear it started it was on before it was phantom shifting. Only happens when I am really pedaling hard and only in middle gears, shifts fine otherwise, hanger looks good, rear suspension pivots are good. Took it to two different lbs and its not repaired.

    Any ideas, love this bike, but it almost put the family jewels at risk today.

  2. #2
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    What about the jockey wheels? I never thought these really did anything, but once i changed mine, some issues went away. I have SLX group but some of the same issues. Also check to see that your chain isnt bent (twisted) in one area, have also had this cause some strange shift problems as youve described.

  3. #3
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    How old is the chain? If your cassette is worn, you will get skipping when you mash hard. If it happens in the gears you use the most, then that would be my guess.
    My name is Chris and I ride a Ripmo now.

  4. #4
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    Not knowing the condition of your chain or cassette.......shifting problems in the middle of the cassette can "usually" be attributed to cable tension. Put your bike on the stand or ride it on the street if you dont have one. Slowly and gradually adjust your barrel adjusters until the jumping or self shifting of the chain disappears. If this works, re-do your whole rear mech set up. Set your high and low limits, then re-attach your cable at the rear with your barrel adjusted half way out. This should put you in the ball park for minor adjustments at the barrel.

    BTW, if two LBS's cant diagnose and correct the problem, you need two new LBS's.

  5. #5
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    Cable tension

    I would agree with the poster regarding cable tension, put the bike on a stand, or just get someone to hold it up in the air whilst you shift up and down the cassette. Does it ghost shift? I had a similar problem where it would work properly in the workstand but out on the trail, where the suspension compressed, it would ghost shift. e.g. when seated stomping on the pedals in a climb or seated spinning the pedals going over a rooty section of ground. I discovered that when the suspension compressed, the cable+outer section that ran under the bottom bracket was too short and pulled tight. You may have to experiment with different lengths of outer under the bb but making this section longer cured my ghost shifting problem. GOOD LUCK!

  6. #6
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    From a condition perspective, everything looks good, thanks for the suggestions. The only place I could duplicate is when I am mashing on the pedals (like mikeerac mentioned - seated in a climb or going over rocks), so I doubt the LBS could duplicate on the stand hence the two wasted trips. I think it has something to do with something flexing and causing it to ghost shift. There is good amount of outer casing under the BB. Take a look at the pictures and let me know if anything is glaring. Thanks forthe suggestions. As far as finding a new LBS, I am pretty good with a wrench (car wise, bikes upkeep is new to me) and at this point the money would be better spent on some tools than taking it somewere.
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    Xtr phantom shift-2012-09-25_17-56-33_104.jpg  


  7. #7
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    Has it been like this since you have owned it or is it something that has come up over time?

    Just off the top, it almost seems like the derailleur is misaligned in photo 2 - looks like the derailleur could use more cable tension. Having a derailleur that is slightly misaligned, would explain why it only skips under harder loads.

    To check the derailleur housing, remove some air from the shock and cycle the suspension while keeping an eye on the rear derailleur.

  8. #8
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    Tough to tell, didnt have an issue when first purchased, rode it for two years, took 3-4 years off and now back on it at least once a week. Was lighter than and dont remember any ghost shifting. I think I'll take a look at your idea of checking to see what it does when it flexs, make some alignment adjustments and see if it is any better. If not punt to a compete cleaning and reset of upper and lower limits. Thanks. Besides this place any other step by step web resources for bike maintenance? I figure its already not working, worst case I can't get it to work any better and off I go to the LBS anyway.

  9. #9
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    ghost shifting is 80% of the time derailleur hanger bent... watch video... you can straighten it, mine was cracked so I replaced in the vid

    Trail Tire TV: Fix ghost shifting


    not that cables and worn drive can't cause the issue.. but a worn drive that has been worn out together usually doesn't have an issue till it's SOOO bad nothing works or when you introduce a new component to the mix (like a new cassette and old chain)

    bad cables will usually give you poor performance through out the whole shifting range unless there is a thread broken/unwinding right at the beginning or end of a housing..


    from those images the cassette is most certainly worn out and you need to replace the cassette and chain.. (and possible the from rings ) If you look at the image I marked you can see the wear, esp in the ring just above the chain,.. guessing these are your most used set..
    Attached Thumbnails Attached Thumbnails Xtr phantom shift-cassette.jpg  

    Last edited by thomllama; 09-27-2012 at 08:38 AM.
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  10. #10
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    Check out the repair section on Parktool.com - you could also search various videos on Youtube.

    Just shift to your highest gear(or lowest if it's a rapid rise rear derailleur) and undo the cable pinch bolt - start from square one. From there, move the derailleur by hand to check the shifting on the highest and lowest cogs - you want to get a close preliminary setting for the high and low limit before re-attaching the cable.

    After that, re-check your high and low limits. Do this by pulling on exposed cable(between stops) to check the shifts, instead of using the shifter to check the shifts. You want to set the limit screws as 'tight' as possible while still allowing a smooth shift. Then, it's a good idea to pull the exposed cable again(while pedaling forward) until it hits the limit, stop pedaling while continuing to hold the cable, then release the cable. From there, pedal forward again until the derailleur returns to it's natural resting position. You will likely notice that the cable is no slightly slacker than when you initially re-attached the cable - go ahead and loosen the pinch bolt and pull the slack out of the line(you don't need to pull hard). Before attaching the cable, you'll want to give the barrel adj(s) a couple CC turns.

    Once you've reached that point, all that is left is setting the cable tension. Using the shifter, make one shift to the next cog. Typically, you'll turn the barrel adj CC(adding tension) until the chain wants to jump to the next cog - this will include some excess noise, so just lessen the tension until the chain runs quiet over the cog you are in. Check the shifts throughout the rest of the cassette.

  11. #11
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    Cable run under bb

    Please post a photo of the cable run under the bb

  12. #12
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    Cable under bb

    Before you do a complete reset of the rear gears, it may be worth letting the air out of the shock and compressing the suspension all the way and checking the cable outer under the bb. Sorry to bang on about it but with the air out of the shock you can see what happens to the cables when the suspension is working. If it wasn't happening before, it may be the difference between your old weight and you current weight (no offence intended). Has the shock got the correct air pressure?
    I would hope after being to two bike shops anything major would have been spotted and the gears correctly set up so may not be worth fiddling with the settings. I would imagine that the 9st bike mechanic test rode it and didn't give the suspension a workout!
    For info i am 6ft and weigh 210lb and had the same problem with my 2004 Epic.

  13. #13
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    new pics, thomllana, you mention the cassette looks worn out, I compared it to my kids new trek (less than 100miles) and it looks almost identical as far as sharpness of sproket points and length of valleys. Plus I think the LBS would have been all over selling me new parts. Anybody else see excessive wear? By the way I liked you hanger video, I may just grab one (cheap enough) to try, it may have been bent considering how many times something has been leaned against it, feel over, or hit a rock in the past years. Check out new pics, I tried to show alignment and the loop under the BB.

    When you say you made outer under the BB longer, are we taking an inch, 3 or half inch? I realize I may have to mess with it to find the optimal length just not sure where to start.

    No offense taken on the weight, Im not a mess, I just have a little extra in the middle, but the bones to carry it. Yes, even if both LBS guys rode it they may have been all of 160, I doubt they could duplicate it. Air pressure is good, I check it occasionally and the shock was rebult about 3 years ago.
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    Xtr phantom shift-2012-09-27_11-36-47_701.jpg  


  14. #14
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    Are you certain it's ghost shifting and not skipping? I have never been able to determine visually when a cassette reaches the point where a new chain will skip on it.


    Good luck,
    Pete
    I can barely get my mouth around it.

  15. #15
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    DAMN! I think that cable under the bb looks ok to me. The only way to really tell is to let the air out of the shock and cycle the suspension through its travel. If you have a stand, put the bike in the ghost shifting gear and peddle the bike whilst moving the back wheel up through the whole travel.

  16. #16
    Just a flesh wound
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    from those images the cassette is most certainly worn out and you need to replace the cassette and chain.. (and possible the from rings ) If you look at the image I marked you can see the wear, esp in the ring just above the chain,.. guessing these are your most used set..[/QUOTE]

    I think it's just worn. Get a chain measuring tool. Park makes a good one. The cassette looks worn. I had to replace mine recently. I replaced the chain and then I got skipping which feels and sounds just like ghost shifting. Replaced the cassette and everything is right again. I waited too long to replace the chain, so I got the chain measuring tool to prevent that from happening again.
    My name is Chris and I ride a Ripmo now.

  17. #17
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    Llama is 100% correct. That cassette is completly worn out. Replace it, and the chain. Check the fronts. In the second photo, the derailleur looks to be almost half a cog out of adjustment as well. If the cassette on your kids bike looks identical......your kid needs a new cassette too!

  18. #18
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    Thanks for the advice dropped the air from the rear shock, at full flex cable under bb doesn't get tight enough move derailler. Did a quick check on chain will waiting for park chain gauge to come in put it up in big front ring pulled chain it comes off enough to almost see a full tooth. So before I go any further a new cassette and chain are in order. Any online suggestion? There was a post which I can no longer find about a company that was having a major sale, I believe it may have been a uk company. Is there a place that identifies what chains and what cassettes will work with which shifters and derailers? Like this SRAM cassettes and chain will work with a xtr RD etc. once again thanks.

  19. #19
    Just a flesh wound
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    Chain reaction cycles has good pricing. It takes a while to get your stuff though. A recent test done by a German Bike magazine says the higher end Shimano chains last longer. I got a 9 speed Dura Ace 7701 for $38. I would recommend the XT cassette. Its strong and durable. Pricepoint is good as well. Shipping is faster and they match price.
    My name is Chris and I ride a Ripmo now.

  20. #20
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    I skimmed the above comments. There are so many things that could cause your problem. I agree with an above poster who said usually old drivetrains act up when you introduce something new. If you have not put anything new on the bike,, at least try chainging out the hanger. It's not that hard and you should have a spare anyeay. Also, check the shifter cables and housing. Old ones can cause problems; and if they are new, sometimes people with full suspension bikes cut the middle piece of housing too short.

    It's nice seeing a 952 still in action.

  21. #21
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    Quote Originally Posted by Pisgah View Post
    I skimmed the above comments. There are so many things that could cause your problem. I agree with an above poster who said usually old drivetrains act up when you introduce something new. If you have not put anything new on the bike,, at least try chainging out the hanger. It's not that hard and you should have a spare anyeay. Also, check the shifter cables and housing. Old ones can cause problems; and if they are new, sometimes people with full suspension bikes cut the middle piece of housing too short.

    It's nice seeing a 952 still in action.
    And before you change a hanger it should be checked with an alignment tool. It can not be eyeballed with any accurately, and it can be realigned.

    Even brand new hangers may not--and likely are not--straight and need to be checked.
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  22. #22
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    Quote Originally Posted by shiggy View Post
    And before you change a hanger it should be checked with an alignment tool. It can not be eyeballed with any accurately, and it can be realigned.

    Even brand new hangers may not--and likely are not--straight and need to be checked.
    what he said!!!
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  23. #23
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    In the uk I would go with chain reaction cycles, merlin cycles
    and Planet X for deals. If you search for particular items you may
    find sites offering deals on individual parts. I have never bothered
    with the high end cassettes and chains but do invest in xtr gear
    cables as they seem to last really well. For cassettes I have used
    SRAM PG950 and 970 or Shimano LX/SLX. For chains I have used
    SRAM 951 and 971 and shimano LX/SLX . Take a look at the bike websites
    and see what chains cassettes you get with new bikes, a lot of companies
    use KMC chains with SRAM or Shimano cassettes. Well that's my two
    pennies worth and I'm sure i will be flamed but that is my real life experience.

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