Seatpost Help!

Discussion in 'HOW TO' started by Big_Daddy_Sloth, Jun 11, 2012.

  1. Big_Daddy_Sloth

    Big_Daddy_Sloth

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    On this bike, no matter how much I tighten the seatpost (clincher?) bolt , the seat post still spins, slightly. By that, I mean it doesn't spin around like the wheel on WOF, but it will turn if I get all wiggly while riding. When I got it, the seat post was rusted in the seat tube and I had to struggle to get it out. I lubed it before putting it back in and now I have this problem.
    A) Did I use too much lube?
    B) Is the seatpost just a hair too small?

    I don't know what to do. :(

    Let me know if you need a better picture.
    Thanks.

    [​IMG]
     
  2. B607

    B607 Pro Member

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    I'd get rid of the lube. Get some laquer thinner and wipe down the tube and run a rag with thinner down the hole. Do you have a chrome seat post? They are notorious for moving around no matter how tight you make it. Gary
     
  3. mikesbikes36

    mikesbikes36

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    what he said ...n mayb try a popcan shim in there :mrgreen:
     
  4. Big_Daddy_Sloth

    Big_Daddy_Sloth

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    Word. Thanks. The seatpost is chrome and the lube is force of habit. ;)
    I'll give it a cleaning and report back.
     
  5. gcrank1

    gcrank1

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    Those seatposts can vary in dia. a fair bit, too. I think the size is more nominal than exact. I have some that I can swap around to get a better fit in a seatube and some that have been clamped so tight they are out of round, so some brass hammer tune up was required. See if you can find somebody with a few more to try out for fit, its hard to cinch one too small tight enough. Ideally you should have to work it in rather than drop in.
     
  6. deorman

    deorman

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    Any chance you're trying to use a 13/16" post on a 7/8" tube?
     
  7. Big_Daddy_Sloth

    Big_Daddy_Sloth

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    As soon as I get some calipers and am in the garage, I'll check. That was one of my thoughts as well. Thanks.
     
  8. gcrank1

    gcrank1

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    Sometimes you can slide sockets (as in socket set) in to get a good fit in a hole and measure that, just DONT drop one down in!!
     
  9. Saverio

    Saverio

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    That's a good question about sizing seat posts.
    Mine is stamped 25.4mm. I went to buy a 1" (forgot to measure the store bought pipe, but i'm assuming OD) pipe and it was WAY too big.
    They only sell a few sizes, 1/4", 1/2, 3/4, and 1.
    Am I interpreting this incorrectly?

    I thought I'd head down to the hardware store and pick up some steel pipes and make mine own post, but can find the right size. My bike is a new Nirve, so I thought it'd use a more common size for aftermarket applications.
     
  10. gcrank1

    gcrank1

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    Nope,'pipe' is measured by the hole in the middle where the fluid flows; add the wall thickness and you end up with what you've got, WAY too big.
     
  11. Saverio

    Saverio

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    Thanks for setting me straight. Learning as I go!
     
  12. Big_Daddy_Sloth

    Big_Daddy_Sloth

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    Also, I want to add that I bought the bike this way. So maybe the person before me did it. And crud! I keep forgetting to borrow the digital calipers from work.
     
  13. gcrank1

    gcrank1

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    Many 'home repair centers' have the General tool brand, fairly inexpensive and mine are all good quality. They have a nice little dial caliper (not sure if its in thou/mm or fractions), but it should do for almost all your bike work.
     
  14. Big_Daddy_Sloth

    Big_Daddy_Sloth

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    Ok, so I finally measured my seatpost tonight. I may need to re-check it, as this is what I got:
    Seatpost 20.65mm
    Seattube 19.53mm/19.94mm

    It was getting dark and I was getting tired. I'll check again tomorrow. But do these sound somewhat right?
     
  15. jackdaw

    jackdaw

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    Yeah bud, a millimeter one way or the other will make a difference. One of the mysteries of the bike world, why seven or eight different seat post diameters? Why not say, three? Two mm apart and you could get to be able to tell the difference by eye. But no. When you buy seatposts they come measured to the tenth of a mm. Good luck!! You'll find one, or find a shim.
     
  16. gcrank1

    gcrank1

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    Got those numbers flipped?
     
  17. Big_Daddy_Sloth

    Big_Daddy_Sloth

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    That was my first thought as well. I'm at work, so let me bust everything out and take pictures.
     
  18. Big_Daddy_Sloth

    Big_Daddy_Sloth

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    Crud. I can't get the pictures to my email. But the new photos show -
    Seatpost: 20.34*
    Seattube: 20.28

    * This is a guess-timate of the average. If I move the digital calipers around andthe seatpost and up and down the length, I get a huge range of numbers. :/

    Any suggestions?
     
  19. gcrank1

    gcrank1

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    Seatpost is out of round (not unusual for the cranking that they take), but it cant fit into a seat tube of smaller dia. and still be too loose.......
     
  20. Big_Daddy_Sloth

    Big_Daddy_Sloth

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    I think that's it, because as I posted previously, when I measured it, I got wildly different readings depending on where I put it.

    Thanks.

    Now what size do you think I need?
     

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