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  1. #1
    Downhill Racer PhilThee's Avatar
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    Aftermarket Clamp-How do you get the size of the seat post clamp correct?

    How do you get the size of the seat post clamp correct?

    My seatpost is 27.2
    Do I simply get a 27.2 seatpost clamp?
    Do they compensate for the amount of material between the post and the clamp?

    Do I have to take a pair of calipers to it?

    It's a 2006 Cannondale R1000
    "I didn't see him/her" is a confession, not an excuse.

  2. #2
    PITLOCK Shop
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    I don't know about an industry standard tube thickness, but I can tell you that your seatpost diameter is not the seattube diameter. My Rocky Mountain Flow uses a 26.8mm seatpost and a 27.2mm clamp.

    I had to use a vernier caliper to measure mine.
    Authorized North American PITLOCK Locking Skewer dealer. http://www.urbanbiketech.com

  3. #3
    Downhill Racer PhilThee's Avatar
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    Quote Originally Posted by Urbanbiketech
    I can tell you that your seatpost diameter is not the seattube diameter.
    Yea I knew that but I didn't word that correctly
    "I didn't see him/her" is a confession, not an excuse.

  4. #4
    Svr
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    Common seatpost clamp sizes are 28.6mm (1 1/8"), 30mm, 31.8mm (1 1/4"), and 34.9mm (1 3/8").

    Measure the diameter of your seat tube where the clamp sits. Seatpost diameter often has little to do with seatpost clamp size, while frame materials often do.

  5. #5
    Svr
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    Quote Originally Posted by Urbanbiketech
    I don't know about an industry standard tube thickness, but I can tell you that your seatpost diameter is not the seattube diameter. My Rocky Mountain Flow uses a 26.8mm seatpost and a 27.2mm clamp.

    I had to use a vernier caliper to measure mine.
    So the seat tube on your frame is only .2mm thick? I think you need to measure again.

  6. #6
    PITLOCK Shop
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    Oops. My bad. It is 28.6mm. I was doing it from memory, but I had a look at the clamp (on which the size is stamped)
    Authorized North American PITLOCK Locking Skewer dealer. http://www.urbanbiketech.com

  7. #7
    Downhill Racer PhilThee's Avatar
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    Quote Originally Posted by Svr
    So the seat tube on your frame is only .2mm thick? I think you need to measure again.
    But on the bright side...

    I'll bet that thing is HELLA LIGHT!!!
    "I didn't see him/her" is a confession, not an excuse.

  8. #8
    weirdo
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    If you have a 27.2 seat tube, you probably need a 31.8 clamp. Don't throw stuff at me if I'm wrong, I would measure it if you can, but if I had to guess, that is what I would say.

  9. #9
    weirdo
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    Wait, I'm thinking deraileur clamps ignore me.

  10. #10
    . Namenda's Avatar
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    My frame takes a 27.2 seatpost, and a 31.8 FD clamp. I use a 32 seat clamp, it works perfectly.

    Phil--are you using a clamp-on or braze-on FD? If clamp-on, you will have an idea what seat clamp to use.

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