Frame/seat tube issues.

Discussion in 'The Lounge' started by JohnE, Jan 2, 2008.

  1. JohnE

    JohnE filthy rascist

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    So my trusty 98 Jamis Dragon has developed issues with the seat tube. My seat will no longer stay up, thats right, I have problems keeping it up. There are no obvious cracks in the tube or around the seat bolt binder area. Can the collar area have stretched out? Bolt is in one peice, nothing else seems amiss to my non framebuilding eye, although there is a strange line around the collar area, inside the seat tube, about a quarter inch down. Any ideas? If it matters, it has a Thomson post in it, and a bolt, not a QR.
    Anybody? Bueller? Bueller?
     
    #1 -   Jan 2, 2008

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  2. jdcamb

    jdcamb Tool Time!

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    Have it reamed out to the next size up. Then replace your seatost with that size. Or shim it out with a beer can.
     
    #2 -   Jan 2, 2008
  3. reflux

    reflux Turbo Monkey

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    Funny, as I've been having similar issues with 2000 Dean hardtail, also with a Thomson seatpost. Part of me is thinking the seatpost has worn down (thinned) in that small section, thus preventing the clamp from applying adequate pressure. How old is your Thomson post? Mine is going on 6 years. Hmm, that doesn't sound good once I put that to words.
     
    #3 -   Jan 2, 2008
  4. HAB

    HAB Chelsea from Seattle

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    Get some special carbon seatpost compound from your LBS. It's basically grease with tiny glass particles in it. It can help stop slipping seatposts.
     
    #4 -   Jan 2, 2008
  5. Cru Jones

    Cru Jones Turbo Monkey

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    Slam it. That's what the cool kids do.
     
    #5 -   Jan 2, 2008
  6. HAB

    HAB Chelsea from Seattle

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    Which is why the "cool kids" are incapable of pedaling their bikes anywhere, so they resort to cruising sidewalks and hucking curbs on their Big Hits. :disgust1:
     
    #6 -   Jan 2, 2008
  7. Cru Jones

    Cru Jones Turbo Monkey

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    While I agree that is the wrong tool for the job, I'm not so sure they're incapable. Pedaling is a little old fashioned. We like to build and ride stuff that requires little to no pedaling. :biggrin:

     
    #7 -   Jan 2, 2008
  8. cheetaprowlerDH

    cheetaprowlerDH Turbo Monkey

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    ^^ why?....
    that pic is going to make me cry... too perfect
     
    #8 -   Jan 2, 2008
  9. johnbryanpeters

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    Ummm... before you try reaming or glass filled grease (ye gods and small fishes...) get out your vernier calipers and measure O.D. of seatpost and I.D. of tube. Are you sure you started out with a correctly sized seatpost?
     
    #9 -   Jan 2, 2008
  10. CrabJoe StretchPants

    CrabJoe StretchPants Reincarnated Crab Walking Head Spinning Bruce Dick

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    Something tells me if it were the wrong size he would have noticed in the past 10 years...
     
  11. DirtyMike

    DirtyMike Turbo Fluffer

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    I am thnking a couple different things from a couple different people.

    1st, Calipers like JBP says, Maybe not to check if you have the wrong size to begin with, but to see if its worn

    2nd Might be time for a new seatpost and clamp. Get something ridged like the thompson, or others like it.

    3rd If that doesnt work, the carbon grease works wonders. Great stuff, slick as hell till you put some rpessure on it.

    4rth, and this is mine, Aluminum dust can be extremly slick, try taking the seatpost out, cleaning it with a decent "hot" solvent and a brush<dishsoap and hotwater works great> and also cleaning the inside of the seat tube in teh same manner, nice long bottle brush should do the trick.

    5th I would only resort to reaming a tube out to the next size as a last resort, for the obvious reason, your taking metal out of it to do so, effectivly weaking the tube. How much are you weaking it? Cant tell you that part, but its a part on my own bike I dont want to fail.
     
  12. loco-gringo

    loco-gringo Crusading Clamp Monkey

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    I bought a Dean Jester used from a guy. It had a 26.8 post he had always ridden. It really needed a 27.2. It happens.
     
  13. johnbryanpeters

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    I dunno - you can crank down pretty hard on a bolt. If you presume no movement normally, I have a hard time coming up with a rationale for a seat post starting to slip.

    Most of the horror stories you hear or read about have to do with tubes stuck in by corrosion, not with them getting loose.
     
  14. DirtyMike

    DirtyMike Turbo Fluffer

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    Yeah, I have seen more than my share of bikes with too small of a post in them, Its amazing how much you can crush a seat tube
     
  15. HAB

    HAB Chelsea from Seattle

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    I kid. Pedaling is fun, so is riding stuff that dosn't require much. Hell, pretty much anything that has to do with riding a bike is fun.
     
  16. -dustin

    -dustin boring

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    my bet is that the seatpost is crimped. is it dropping and dropping and dropping, or does it seem to only drop to a certain point?

    Is the bolt in the binder greased?
     
  17. JohnE

    JohnE filthy rascist

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    Front Range, dude...
    The post already is a Thomson, and it is new as of about 18 months ago...

    Yes, it is the right size...this aint my first rodeo.

    It is slipping, seemingly to about the same level every time, now that I thhink about it. There is no evident crimping on or in the seat tube.

    The binder is greased, but what if any effect would that have on slippage? You lost me there...

    I am thinking beer can shim, but first I need to find someone who drinks beer from a can! That failing, the carbon grease.
     
  18. brungeman

    brungeman I give a shirt

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    you need to try some Dale's Pale ale... prolly the best beer you will ever drink from a can! You will thank me when you do try it :thumb:
     
  19. -dustin

    -dustin boring

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    Crimping would be on the post, not seattube.

    Bolt being greased reduces friction allowing proper torque to be achieved.
     
  20. Wumpus

    Wumpus makes avatars better

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    The Thomson in my Jamis(2004) slipped when it was new. Loco gave me Stinkyboy's Salsa Liplock binder:busted:, and I haven't had any problems since.
     
  21. JohnE

    JohnE filthy rascist

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    No, also no crimping on the post...its only been in one bike, so it stnds to reason that it and the tube would be crimped.

    I think I will call the Mythbuster geeks. And then get the carbon grease.
     
  22. DirtyMike

    DirtyMike Turbo Fluffer

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    Try this, take your seat post out, reach in the tube with your finger as far as you can, and see if you can wipe anything out of the tube, like aluminum dust, I am just curious, I have seen this alot and seen seat posts slip because of it.
     
  23. CrabJoe StretchPants

    CrabJoe StretchPants Reincarnated Crab Walking Head Spinning Bruce Dick

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    TRUE THAT!


    I couldn't think of the came of the company when I went into the store looking for some (figured keep my eyes open for the only IPA in a can).

    Me - *looks around*
    Employee - "Can I help you find something?"
    Me - "Yea, I forget who makes it, but it's an IPA that comes in a can."
    Employee - "Erm....we have bottles of IPAs."
    Me - "O RLY?"
     
  24. JohnE

    JohnE filthy rascist

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    Stuck finger in, rubbed it around. Came out slightly dirty and greasy, no dust.
     
  25. DirtyMike

    DirtyMike Turbo Fluffer

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    Where in Socal are you at?
     
  26. JohnE

    JohnE filthy rascist

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    Stuck in the desert between Bakersfield and LA...Edwards AFB.
     
  27. DirtyMike

    DirtyMike Turbo Fluffer

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    Damn, Was hoping you were a little closer to me. Guess you dont want to drive to SB area to come to my shop. If your down this way though, gimme a holler