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  1. #1
    Motobecane Custom
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    27.0 Seatpost in a 27.2 Frame?

    I bought a seatpost online and didn't realize there was a difference between 27.0 and 27.2

    My bike frame is 27.2 and the seatpost is 27.0 will I have problems getting the seatpost to stay in place or will tightening the seat collar be enough to keep it in place? What other problems will I encounter?

    Thanks

  2. #2
    Senior Member
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    More info needed. Frame material & type of seatpost clamp. ie. welded to the frame or not. Don't feel bad there are 40 different seatpost sizes.

  3. #3
    cab horn
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    You'll need to shim it with a beer can to make up that .2. I suggest you not tighten anything down on a seat post which diameter does not correspond to your frame.

    The shim is only temporary. You want to replace that with the correct size when convenient.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  4. #4
    Motobecane Custom
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    The frame material is 7005 Aluminum and the clamp is not welded. I'm hoping I don't need to replace the seatpost. I bought it on ebay it was kinda expensive.

  5. #5
    Senior Member
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    I probably wouldn't force the seatpost bolt on an aluminum frame. I'd probably do it on a steel frame I didn't care too much about. Steel will bend, al will break.

    get a new seatpost, or you might harm the frame screwing the seatpost bolt too tight or be unable to keep the post from sliding into the seat tube. the beer can shim is a temp solution at best, but will work.

  6. #6
    Senior Member
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    I think you are in trouble as beer cans are 0.2 mm thick, which would make a difference of 0.4 mm on diameter. Before I tried selling that post on e-bay, I would see if high temp aluminimum foil tape for furnace ducts would allow you to get a good grip on the post.

  7. #7
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    Quote Originally Posted by chosonman
    I bought a seatpost online and didn't realize there was a difference between 27.0 and 27.2

    My bike frame is 27.2 and the seatpost is 27.0 will I have problems getting the seatpost to stay in place or will tightening the seat collar be enough to keep it in place? What other problems will I encounter?

    Thanks
    WHY NOT BUY THE RIGHT SIZE SEAT POST!

  8. #8
    Member
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    For a 2 mm difference, a pressed soda can works FINE!!! just wrap it around, the one on my beater is holding up for a Long time...anything more than 2mm, get a Shim, or new post.

  9. #9
    me have long head tube TallRider's Avatar
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    Yeah, you should buy the right size seatpost, definitely. 27.2mm is the most common size, should be easy to find one for not too expensive, and you can sell your expensive 27.0mm post on eBay.

    I've seen a 27.0mm post on a frame built for 27.2mm, and it was a steel frame, and the seatpost clamp was noticably crimped shut - not something I'd trust for the long-term on an aluminum frame.

  10. #10
    Motobecane Custom
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    Anyone in the DC area interested in a Thompson Elite Seatpost 27.0 x 250? I'm asking $40.00

  11. #11
    cab horn
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    Quote Originally Posted by chosonman
    Anyone in the DC area interested in a Thompson Elite Seatpost 27.0 x 250? I'm asking $40.00
    Go shill your wares after you paid up.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  12. #12
    MADE IN HONG KONG
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    VERY interested if it is silver

    Actually, a SParks can is just under .004" which is approx .1mm, so a shim wrapped all around will increase the dia by .2 mm . There were a few posted that gave different reads, and I wanted to confuse things further.
    If you are not having any fun, it's all your fault

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