It seems to me that SRAM used not rivet to hold all the cogs in one place, but long screw. This screw looks like a hex one, but I tried hex keys I have and I didn't find a match. Unfortunately the head is so small I cannot be sure it is hex in the first place (and not for example pentagonal).

So my question is am I correct with the "screw lead"? If yes, is it a hex one indeed? And what size?

I am asking to avoid drilling it through. Screw is always nicer to work with also because I can screw it back.

  • 2
    Which ones did you try? I don't know about SRAM cassettes in particular, but I'd except the screws to be metric, not inch-based.
    – ojs
    Commented Oct 12, 2019 at 10:42
  • @ojs, ah, good point, I forgot about it. Could you please post this as an answer. Commented Oct 12, 2019 at 11:07
  • Not yet, since I have no idea if they are actually metric.
    – ojs
    Commented Oct 12, 2019 at 11:37
  • 1
    I found a photo where someone appears to use a multi tool to unscrew it: rowerowybazar.com.pl/web/files/user_ad/…
    – gschenk
    Commented Oct 13, 2019 at 0:09
  • They also mention hex in the description: "Kaseta jest w pełni rozbieralna za pomocą imbusa." Imbus is a tool company that's synonym with (metric) hex key in parts of Europe.
    – gschenk
    Commented Oct 13, 2019 at 0:12

1 Answer 1


Hex bolts on bicycles are usually metric, and it seems that the bolts holding the cassette together are too. Inch based hex key sizes fall just in between so that none fits.

  • Relevant - the bike's cassette is a fairly dirty area, and grit could be impacted in the fitting, enough to upset the correct-sized tool.
    – Criggie
    Commented Oct 13, 2019 at 8:05

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