Seatpost collar

Posted on
  • Wanted:

    I'm looking for a black or silver seatpost collar. 27.2mm please?

    To clarify, this sits around the top of the seat tube and secures the seatpost when tightening.

    Has anyone got one in their spares box please?

    Please PM.


  • I’ll check the garage tomorrow mate 👍

  • For a steel or Alu frame?

    Pm sent

  • I don't think it will be a 27.2mm clamp unless it's really weird, since that's a standard seatpost size, not a seat tube size.

    "There are five standard seat tube diameters on the market: 28.6mm, 30.0mm, 31.8mm, 34.9mm, and 36.4mm"

  • Thanks for your help.

    This collar is for a Boardman hybrid so I'm guessing a standard sizing. Having measured the diameter across the top of the seat tube, this also measures 27.2mm but it looks like I might the next size up so if anyone has a 28.6mm collar, please let me know.


  • 27.2mm seat tube? Wow. What's the seat post diameter then?

  • I am guessing the frame is aluminium?
    I would recheck your measurements or get the seatpost diameter.

    28.6mm collars are usually reserved for steel frames with thinner tubing and around 27.2 seatposts
    Alu is thicker and usually takes a 31.8.

    Thats been my experience anyway

  • Thanks again for your continued help on something which should be quite simple.

    I have attached a couple of images which might help to clarify the size of collar I need.

    1 Attachment

    • IMG_20190811_180037.jpg
  • Seatpost.

    1 Attachment

    • IMG_20190811_152937.jpg
  • That measuring tape doesn't look like it's on the widest point of the seattube.

    Also as noted above - if your post is 27.2 then the collar can't be (unless your frame is invisibly thin)

  • Wrap a piece of paper around the seat tube and mark where it overlaps. Measure that distance with a ruler and divide by pi.

    A 28.6mm seat tube will be 89.8mm around
    A 30.0mm seat tube will be 94.2mm around
    A 31.8mm seat tube will be 99.9mm around you should be able to tell the difference.

  • I’d be amazed if this isn’t 31.8mm!

  • Chaps,

    Thank you all for your help.

    Now all sorted.

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Seatpost collar

Posted by Avatar for Julian_Stock @Julian_Stock