I recently moved, and had to take off the seat to my bike while I moved. I was surprised to find when I arrived and settled that I couldn't find the clamp to my bike seat. I managed to find a new bike seat clamp, but it's not obvious how I'm supposed to install it. What should I do? I've included a photo of my bike seat, without the clamp. Don't be confused by the bike behind it, the black seat post and seat and red body is the one I'm working on.

My bike is a GT avalanche, unmodified from the store.

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  • Traditionally the top of the seat tube has a slit in it and the clamp fits over the top 1/2" or so of the tube to compress the tube onto the post. But with modern bikes there are no doubt other schemes used. Commented Sep 1, 2012 at 16:55
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    (It should be noted that seat posts and seat tubes come in several different diameters. Though most clamps are made from fairly flexible metal they will only adapt through a small range of sizes, so there's no guarantee that a randomly chosen clamp will work on a particular bike.) Commented Sep 2, 2012 at 0:30
  • @DanielRHicks: Thanks for the tip. I did manage to buy the right size, but I realized when I got home I had no idea how to install it, so... Commented Sep 2, 2012 at 1:50

2 Answers 2


Figured this one out after a bit of work. If you look from the back side, you will see that there is a gap in the metal. This is to allow compression to clamp the seat tightly. Put the clamp on the frame of the bike, and if there is a quick release, tighten the nut hand tight. Then put the seat at the right level, facing the right direction, and close the quick release.

If there isn't a quick release, tighten the nut hand tight, put the seat in place, and tighten it the rest of the way using the correct tool to do so.


Position the clamp so that the open section of the clamp is oriented to the slot in the frame. If the frame slot faces the rear the opening in the clamp should also face the rear.

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    An anonymous user attempted to edit this post to "correct bad advice." His/her comment was as follows: I read in Leonard Zinn's book that you shouldn't line up the slots...especially on carbon fiber posts.Too many pressure points in the same area. See "Zinn and The Art of Mountain Bike Maintenance"
    – jimchristie
    Commented Feb 25, 2013 at 20:37

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