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  1. #1
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    New question here. Problems With My New Rear-Derailleur

    I recently switched out an old rear-derailleur on my Gary Fisher 2001 Tassajara with a Shimano RD-M760 Rapid-Rise Derailleur. After making what I thought were the necessary adjustments, I still have a problem with ghost shifting under load (i.e. when pedalling). If I have my bike on a stand, I can quickly shift the gears and the derailleur indexes just fine. Here are the original specs for my bike and what I changed:

    Crankset: Shimano Acera-X 42/32/22
    Chain: IG-31 --> Switched to Shram Silver 8-speed chain.
    Cassette: SRAM 5.0 11-32, 8-speed
    Rear Derailleur: Shimano Deore SGS --> Switched to M760 SGS
    Shifters: Shimano Alivio RapidFire+

    Hopefully, this ghost-shifting under load problem will be obvious to someone. Thanks in advance for any help!

  2. #2
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    Quote Originally Posted by jonect
    I recently switched out an old rear-derailleur on my Gary Fisher 2001 Tassajara with a Shimano RD-M760 Rapid-Rise Derailleur. After making what I thought were the necessary adjustments, I still have a problem with ghost shifting under load (i.e. when pedalling). If I have my bike on a stand, I can quickly shift the gears and the derailleur indexes just fine. Here are the original specs for my bike and what I changed:

    Crankset: Shimano Acera-X 42/32/22
    Chain: IG-31 --> Switched to Shram Silver 8-speed chain.
    Cassette: SRAM 5.0 11-32, 8-speed
    Rear Derailleur: Shimano Deore SGS --> Switched to M760 SGS
    Shifters: Shimano Alivio RapidFire+

    Hopefully, this ghost-shifting under load problem will be obvious to someone. Thanks in advance for any help!
    I forgot to mention that I changed out my cables and cable housings. I've been using the bike enough to think that it has stretched out the cables (at least 6 rides). Another thing, I mainly ride with the chain ring in the middle gear and the cassette in Low and 2nd gear (2 cogs with the most teeth) since I changed out the derailleur. When riding in this configuration, there is no problem. As I move from 3rd gear to 8th on the cassette, the ghosting starts. I've tried adjusting while riding in an open parking lot with no luck.

  3. #3
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    Typically on a HT when you have ghost shifting under load it is due to a bent derailleur hanger.

    If you are positive that the rear derailleur adjustment (indexing) is correct, and you have replaced all of those componets I would check that next.
    There is no added value to my participation - in fact, just more confusion.

  4. #4
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    It could be a bent hanger but I think its just adjustment. If no amount of adjustment solves the problem the its almost certainly the hanger.

    How the bike behaves on the stand can be very different from under load. Make sure to tighten the cable even farther. Turn the barrel adjuster about a turn or two extra. Ghost shifting can indicate the cable is too loose the the chain is riding against the next cog so the ramps keep trying to catch it.

  5. #5
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    Where did you attach the cable to the rear derailleur? Rapidrise requires connection to the front of the bolt not the rear.
    Quote Originally Posted by Hecubus
    It could be a bent hanger but I think its just adjustment. If no amount of adjustment solves the problem the its almost certainly the hanger.

    How the bike behaves on the stand can be very different from under load. Make sure to tighten the cable even farther. Turn the barrel adjuster about a turn or two extra. Ghost shifting can indicate the cable is too loose the the chain is riding against the next cog so the ramps keep trying to catch it.

  6. #6
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    Quote Originally Posted by lebikerboy
    Where did you attach the cable to the rear derailleur? Rapidrise requires connection to the front of the bolt not the rear.
    Could you elaborate on this? I switched from a high to a low normal derailleur, and the cable appears to connect in the same place.

    Thanks,

    Larry

  7. #7
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    Quote Originally Posted by lebikerboy
    Where did you attach the cable to the rear derailleur? Rapidrise requires connection to the front of the bolt not the rear.
    Uhm, no it doesn't. It clamps from the back the same as ever.

  8. #8
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    I disagree. If you look at the connecting bolt (at least on my 8 speed XTR) on the derailleur it's designed to be passed over the front of the bolt rather than the rear.
    Quote Originally Posted by Hecubus
    Uhm, no it doesn't. It clamps from the back the same as ever.

  9. #9
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    and, also, arent the newer SRAM chains not compatible with the older SRAM cassettes? i remember i read that somewhere, might've been the 9spd chain though

  10. #10
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    Quote Originally Posted by lebikerboy
    I disagree. If you look at the connecting bolt (at least on my 8 speed XTR) on the derailleur it's designed to be passed over the front of the bolt rather than the rear.
    I'm not sure we're on the same page here. I thought you were saying you had to run the cable in a sort of loop and clamping it from the front cut end pointing back. Are you refering to the part where the groove for routing it over or under the bolt is located? I think I see what your saying. Yes its opposite on RR but I think its self explanatory (for most) since the clamping side is grooved to fit the cable.

  11. #11
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    IMO, it doesn't sound like ghost shifting, it sounds like skipping on the cassette. You said you replaced your chain, and that the certain gears you use alot don't ghost shift. I think the chain has stretched into these gears (worn out), and when you go into gears you normally don't use, the chain does not mate with cogs.. causing skipping (or what seems like ghost shifting).

    Possible, that when you changed your cables, you maybe made the housing too short/too long?

    Bent rear deraileur hanger is another idea.


  12. #12
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    Quote Originally Posted by bike_freak
    IMO, it doesn't sound like ghost shifting, it sounds like skipping on the cassette. You said you replaced your chain, and that the certain gears you use alot don't ghost shift. I think the chain has stretched into these gears (worn out), and when you go into gears you normally don't use, the chain does not mate with cogs.. causing skipping (or what seems like ghost shifting).

    Possible, that when you changed your cables, you maybe made the housing too short/too long?

    Bent rear deraileur hanger is another idea.
    From all the advice on my original problem, I decided to try two things: Put my old chain back on and also check for a bent derailleur hanger. I put the old chain back on since I didn't want to 'bend' my hanger if it didn't need it and found that my ghosting stopped. I made no other adjustments.

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