Can anyone please tell me the bolt size required to attach a flat mount hydraulic disc brake (SRAM replacement) to a set of Boardman carbon forks please.

  • The part manufacturers (either SRAM and/or Boardman) should be able to tell you -- you will probably need the part/model numbers. Another option is to visit a local bike shop - this is a good opportunity to find one that you like.
    – Armand
    Jul 25, 2021 at 21:47

1 Answer 1


I would guess that its a metric thread, probably a M5 x 0.8.

You can check by taking out a water bottle cage bolt and trying that in the brake mount temporarily.

If you don't have any bolts for your frame, what happened to them? If you've removed a caliper then just reuse the old bolts.

If the old bolts are damaged, use a thread gauge and a micrometer/caliper to measure the thread's specs.

  • 1
    This is not a good answer, because its generic. A better answer would relate to this specific brand of fork and its mounts.
    – Criggie
    Jul 26, 2021 at 1:05

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