How do I remove a compression plug (aka. expander bung) like this one?

compression plug top compression plug side

Most guides I could find assume that there's a 6mm hex Allen opening that allows tightening/loosening the plug (example pictured below, dark hex shape) but that's clearly not the case with mine.

With hex

I read there are designs that require screwing in the bolt partially and hitting it with a hammer until the expander's loosened but I'd rather ask first. The → REMOVE and INSTALL ← markings seem to suggest that there's another way to remove it.

Note that the 2mm gap visible on second picture was caused by the plug being loose enough to be pulled up when tightening the top cap - the spacers can rotate freely and the whole fork gets slightly loose after a few days. Adding another spacer only caused the plug to slide out a bit further so I'd like to anchor the expander properly.

  • 2
    I think the felt is a re-brand KCNC compression plug so you could search that. Also there may be a smaller hex screw at the bottom of the threaded shaft (possibly 3mm) that may be able to be loosened. Use a bright torch to see.
    – DWGKNZ
    Commented Aug 15, 2014 at 0:25
  • 1
    Looks to me like you just twist the top plate clockwise. Have you tried that? A strap wrench or jar opener might help if it's really stuck.
    – alex
    Commented Aug 15, 2014 at 3:59
  • I guess it would be possible to twist the plate but not likely without those tools. Fortunately, it turned out that there indeed was a hex screw at the bottom :).
    – kryger
    Commented Aug 15, 2014 at 20:14

2 Answers 2


@DWGKNZ was right, turned out that there was a 3mm hex at the bottom. Picture of the removed plug, upside down:


Thanks for quick and useful advice.

  • 4
    In my case it was a Torx key, but it was indeed hidden there and I could only find it because of this post. The instruction manual just says "Install the carbon compression plug" but doesn't specify how or with which tool. Thank you!
    – palako
    Commented Jun 23, 2020 at 14:38
  • I have a very similar Felt plug that has a 4mm hex.
    – NPE
    Commented Apr 17, 2022 at 9:25

I had to mess with one of these. It is a horrible design so I replaced it.

It tightens by rotating the top clockwise which is impossible to do when the plug is installed.

  • 2
    Welcome to Bicycles SE. We're looking for answers with more detail. Please consider editing your answer to explain how you removed it. A short post like this that doesn't really answer the question is likely to get downvoted, flagged for moderator intervention, and possibly deleted.
    – jimchristie
    Commented Aug 30, 2023 at 20:14
  • 1
    Welcome to the site - check out the Accepted answer which shows a 3mm hex socket down the middle to hold the mechanism still. Are you saying your's was the same brand but had a different design ?
    – Criggie
    Commented Aug 30, 2023 at 23:44

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