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Thread: this epic skips

  1. #1
    Devo
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    this epic skips

    This Epic skips gears.
    its my buddy's bike, and I cant figure it out.

    I've replaced the entire drive train
    new chain
    new cogset
    new chainrings

    straightened the rear derailleur hanger with a park derailleur alignment gauge

    its got XO shifters and derailleur
    new cables and housing
    the rear housing is all one piece, zip tied into position with enough slack in the loops to let the cable/housing move when needed.

    it most notably skips when in the middle ring
    mid cogset
    under pressure
    sometimes it ghost shifts immediately after he lets up on pedal pressure.

    any ideas?
    I need to get this bike fixed.

    sometimes I think there is something flexing that causes the derailleur to make it shift.

    sometimes I think there is something cracked, and the rear end flexes around
    but I can't find anything
    and it doesn't make any creaking sounds.

    sometimes I wonder if it has something to do with the suspension movement
    i.e. pedaling up a rocky section when the suspension is working...
    Attached Thumbnails Attached Thumbnails this epic skips-img_4114.jpg  

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  2. #2
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    If you think the suspension movement may be causing it, let most of the air out of the rear shock so you can cycle the suspension by hand and look to see if the rear derailleur is moving.

  3. #3
    Devo
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    Quote Originally Posted by dkbikes4life
    If you think the suspension movement may be causing it, let most of the air out of the rear shock so you can cycle the suspension by hand and look to see if the rear derailleur is moving.
    good idea!
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  4. #4
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    Step number 5 click here

  5. #5
    Devo
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    Quote Originally Posted by Jacobus
    Step number 5 click here
    another great idea!

    this bike keeps eating up time
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    "Bicycle Lifestyle, realized." D.G.

  6. #6
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    is the cassette tight? is the freehub loose? (bearings or bushings worn, i have seen this on old Mavic hubs where the bushing is all worn out)

    hard to diagnose from a keyboard though. :/
    My wife's website....
    Allison Mann

  7. #7
    Devo
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    well, dam

    I can't get this bike to quit skipping.

    I even changed the rear derailleur
    everything is squared away.
    what I notice is that there is a bunch of flex between the BB/rear triangle

    I'm thinking about measuring the flex...
    maybe a video?
    www.AsanaCycles.com
    "Bicycle Lifestyle, realized." D.G.

  8. #8
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    Sounds like the the derailleur cable might be too short or routed wrong......
    13' Lynskey M290
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  9. #9
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    Maybe your free hub is worn out. Either the paws or the inside spline that the paws ratchet up against may be worn out. For example, my OEM Shimano free hubs normally last for about one year before they start to skip randomly. If your Epic has a Deore RH-M525 hub like most Specialized Mountain bikes have, then you probably need to replace the free hub body. Before you or LBS installs it, pull the seal off the back and drip about 5 to 10 drops of 30 or 50 weight motor oil in it and re-install the seal. The added oil will insure that the paws are well lubricated so they donít wear out prematurely. Also drip oil into the back of the free hub every time you rebuild/repack your hub bearings with grease.

  10. #10
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    Does the housing routed under the bottom bracket have enough slack to account for suspension movement?

  11. #11
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    Quote Originally Posted by Berkley
    Does the housing routed under the bottom bracket have enough slack to account for suspension movement?
    x2.

  12. #12
    Devo
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    I just fixed it!

    loose derailleur hanger.

    the #30 torx bolt was about 1/2 turn loose.

    this thing has driven me crazy
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  13. #13
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    Glad you got it fixed. Its normally the small stuff. Although you said the rear of the bike is flexing a lot. Is there something wrong there still?

  14. #14
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    Quote Originally Posted by dkbikes4life
    Glad you got it fixed. Its normally the small stuff. Although you said the rear of the bike is flexing a lot. Is there something wrong there still?
    Thought the same thing when I read it! Maybe the bearings for the suspenion need to be replaced???

    Glad to hear you fixed it!

    Chris

  15. #15
    Devo
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    this bike has been a very interesting exercise

    this is a buddy's bike
    I have no idea how long he has had it
    every time I had ever been around him while he was riding it, it always skipped, popped, banged, etc...

    I started working on it, and initially I figured it just needed a new drivetrain, and straighten the derailleur hanger... typical stuff.
    so I do the work and go thru the entire bike, noting a handful of things...
    I ride the bike around and it runs fine.

    we go for a ride, and bang! pop! it jumps, and skips.
    I can't stand it.

    I get the bike back the other day, and start into it.
    as a last ditch effort I started this thread.

    I can recall in 90's often times a bike may shift under load, I'm thinking a bike like a Pro-Flex or something, and it had me thinking that maybe there was something to do with the Brain setup, inertia valve, stable platform valve, suspension set up, etc...

    I kept wondering if the bike was cracked.
    I've seen road bikes shift under load, because of a cracked bb shell, etc...

    I re-work all sorts of stuff on this bike. Its pathetic.
    just for the heck of it, I pull out a Torx bit, and sure enough... the freaking bolt turns!
    I could hardly believe it.

    the rear derailleur hanger was tight, when I'd check it my bare hand, but obviously it was moving when putting pressure to the pedals.

    weird enough, I'd ride the bike, and apply the rear brake, the ghost shifting was minimized.
    applying the front brake only and putting pressure to the pedals, made it skip...

    after tightening the #30 (I'm pretty sure its a #30) Torx, its solid. no skipping, shifts up and down under pressure, etc...

    I think this has been an issue with this bike for at least a year.

    my buddy kept telling me these stories of shop wrenches telling him that it was the way he was riding. that its his fault for the way the bike was performing. As if he wasn't riding the bike correctly.

    ok... I can see that comment coming out. But really, its a freaking inanimate object. Its a tool. Its a bike. It should perform under all those less than optimal driving techniques.

    of course, its not that great of an idea to cross chain, etc...
    but the reality is that people do it all the time...

    needless to say, I'm glad to have solved this issue with the bike.
    Attached Thumbnails Attached Thumbnails this epic skips-page_123.jpg  

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  16. #16
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    It's funny how the simplest thing can cause a world of problems.

    Now all you have to do is pull that bolt off and Loctite the bejesus out of it... make sure it's not going anywhere!
    Brought to you by rocks.

  17. #17
    Devo
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    this bike has started to skip again...
    I'm looking for a torque spec on this #30 Torx bolt.
    any ideas where I can find that?

    thanks
    d-
    www.AsanaCycles.com
    "Bicycle Lifestyle, realized." D.G.

  18. #18
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    Try taking a link out of the chain?

  19. #19
    Gravity's Gone
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    Have you tried a different rear skewer? I've seen bent and or worn ones cause these types of problems.

  20. #20
    Devo
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    I wrenched on this bike for buddy and it took forever to figure this issue out.
    it came down to that #30 Torx bolt being loose

    he is thinking about buying a new derailleur hanger and bolt
    I want it to torque it down to spec

    I think its crazy that this is a recurring issue.
    www.AsanaCycles.com
    "Bicycle Lifestyle, realized." D.G.

  21. #21
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  22. #22
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    Quote Originally Posted by SelfPropelledDevo
    I wrenched on this bike for buddy and it took forever to figure this issue out.
    it came down to that #30 Torx bolt being loose

    he is thinking about buying a new derailleur hanger and bolt
    I want it to torque it down to spec

    I think its crazy that this is a recurring issue.

    That would probably be the best idea. I've never seen a torque spec on hanger bolts, but I would ask your LBS. You could always Loctite it on there so it doesn't loosen as easily
    Brought to you by rocks.

  23. #23
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    Don't ever bend a derailleur hanger back as a permanent solution. That is a great way to get home if you bash it on a ride, but every time it bends it gets weaker. Then it will just keep getting easier and easier to get ****ed up. Derailleur hangers are meant to be expendable, they are supposed to be the weak point to protect your frame (those specialized hangers are especially weak, i have to replace mine every other month or so). Loctite is always a good idea, and just snug it up good and tight, don't worry about torque spec, you will probably want higher than specialized officially specs anyways.

  24. #24
    Devo
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    I'm so busy these days its amazing.
    this bike is going to fall into a work flow, hopefully sooner than later.
    I've got Dealer Days for Sea Otter that I'm heading up
    just finished a training camp
    got another gig coming up
    and an invite with a US Continental Pro team to wrench and see how things work out...

    busy is good!
    www.AsanaCycles.com
    "Bicycle Lifestyle, realized." D.G.

  25. #25
    Devo
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    Quote Originally Posted by JefedelosJefes
    Don't ever bend a derailleur hanger back as a permanent solution. That is a great way to get home if you bash it on a ride, but every time it bends it gets weaker. Then it will just keep getting easier and easier to get ****ed up. Derailleur hangers are meant to be expendable, they are supposed to be the weak point to protect your frame (those specialized hangers are especially weak, i have to replace mine every other month or so). Loctite is always a good idea, and just snug it up good and tight, don't worry about torque spec, you will probably want higher than specialized officially specs anyways.
    this is just "alignment". Not re-bending a totally destroyed hanger. using park derailleur alignment gauge.
    www.AsanaCycles.com
    "Bicycle Lifestyle, realized." D.G.

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