• 12-11-2012
    Spillway
    1 Attachment(s)
    overclamped carbon seatpost
    I rolled the dice on a FSA carbon seatpost off ebay. I may have crapped out.

    The seatpost shows signs of over-clamping. It looks like the post was overclamped, then the person slide the seatpost to a different position and then overclamped again. The result is two shallow indentations (maybe 1 mm deep) along the back of the post. However, even with a small magnifying glass, I couldn't see any cracks. My hope is that the indentations are just the clear coat.

    Being at the back of the seatpost, the indented areas would be under compression. So maybe less likely to form a crack? However, it is a setback seatpost, so it would possibly create a stress concentration that would lead to buckling?

    Anyone with some carbon knowledge have thoughts on this?
  • 12-11-2012
    lawfarm
    Can you rotate 90 degrees so we can see if there's truly an indentation, or if it's just in the clearcoat?
  • 12-11-2012
    PMK
    Where do you plan to clamp it, above or below the indentations?

    FWIW, fiber construction works well in tension not compression. Compare it to tying your shoes. Pretty easy always pulling to get them tight and tied, trying to push the shoelace would not work well.

    PK
  • 12-11-2012
    Stumpjumpy
    My FSA setback carbon post began to fail shortly after being over-clamped like that by a kid at the LBS (the kid trq'ed it so hard the clamp was stretched/distorted). Listen for a cracking sounds to ensue.
  • 12-20-2012
    loggerhead
    same thing happened with my ec90 post. Now it has smaller spider crack. Sucks but I'm waiting for a catastrophic failure to get a dropper post.
  • 12-23-2012
    Yogii
    I would not use that post...a catastrophic failure may be in your future. Seems like the rider has very little post exposed. With little post exposed, the flex part of carbon is neutralized. Why not just take a strong aluminum post and cut it to desired length? Remember that you want the end of the post and inch or more below the top tube intersection.
  • 12-23-2012
    kbike01
    Discard the seatpost asap.