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  1. #1
    These go to 11. DavidLee's Avatar
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    27.2 seat post, will a 28.6 clamp work?

    Hey guys, sorry for so simple a question. I have a 27.2 mm seat post with a QR clamp & want to get a bolt style clamp. I cannot find a 27.2 clamp anywhere. Am I looking for the wrong size clamp, are clamps supposed to be sized larger than the seat post? Should I just be looking for a 28.6 mm clamp which seems to be everywhere? Again, sorry for the simple question but I'm lost on this one.

    Thanks all.

  2. #2
    Senior Member mattface's Avatar
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    I don't know the answer, but I'm going to guess.

    the seatpost is 27.2 typical seat tube walls are .7 mm thick. seatpost diameter+ (seat tube thickness x 2) = 28.6

    Like I said I don't know, but this seems a logical deduction.

  3. #3
    Senior Member Retro Grouch's Avatar
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    Quote Originally Posted by DavidLee
    Hey guys, sorry for so simple a question. I have a 27.2 mm seat post with a QR clamp & want to get a bolt style clamp. I cannot find a 27.2 clamp anywhere. Am I looking for the wrong size clamp, are clamps supposed to be sized larger than the seat post? Should I just be looking for a 28.6 mm clamp which seems to be everywhere? Again, sorry for the simple question but I'm lost on this one.

    Thanks all.
    Sometimes one measurement is worth a thousand guesses.

    Wrap a piece of paper around your seat tube where the clamp goes. Mark where the paper overlaps. Measure that distance carefully with a millimeter ruler. Divide by 3.14. Buy that size clamp.

  4. #4
    Senior Member Old_Fart's Avatar
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    I have two bikes that have 27.2 seatposts and they have different clamp sizes.
    Only way to be sure is to measure it.

  5. #5
    Dave TRUMPHENT's Avatar
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    Go below. All you need really is a nut. Not a cashew!


    http://www.nashbar.com/profile.cfm?c...eid=&pagename=

  6. #6
    Senior Member Grand Bois's Avatar
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    Quote Originally Posted by TRUMPHENT
    Go below. All you need really is a nut. Not a cashew!


    http://www.nashbar.com/profile.cfm?c...eid=&pagename=
    That's a nut and bolt, not a clamp.

  7. #7
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    what frame are you using ? seat post size doesnt matter, its the external diameter of the seat tube you need to know.

    if its a steal frame it will probably be a 28.6 clamp since steel tubes have thinner walls, if its an alloy frame it could be anything, reer to the manufacturers website.

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