What are the exact dimensions of Shimano disc brake split (cotter) pins, such as part nr. 25 (Y8DB06100) on BR-MT410 caliper (https://si.shimano.com/en/ev/BR-MT410-4663)?

  • Looking to buy generic replacements in bulk
  • Not sure if sizes of these differ on different models of Shimano calipers, information on that would be appreciated as well
  • 1
    There are 3 different sizes/shapes. Commented Jun 16, 2023 at 17:09
  • 2
    They are sold with the brake pads, so it may not be relevant to buy them separately in bulk.
    – Rеnаud
    Commented Jun 21, 2023 at 7:32
  • 1
    @Renaud I do not always replace pads when doing bleed or deep clean - they are often reasonably uncontaminated and have a lot of miles left in them. And where I am, in Denmark, Shimano original pins as separate item seem ridiculously overpriced compared to bulk packs of 100 excellent automotive/construction stainless pins that are available in all kinds of sizes. Commented Jun 21, 2023 at 15:31

1 Answer 1


Here's the results of my measurements with an electronic caliper set on millimeters. This pin came with Shimano's GO4S metallic pads spec'd for use in BR-M6100, BR-M8100 calipers among others. Not pictured:

Width of metal making up the cotter pin: 2.37-2.40mm.

Girth of the closed portion of the cotter pin (the two ends of the metal where they come together after forming the round eye): 2.53mm.

Length of tail (longer side one grasps to pry apart pin): 3.05mm

cotter pin

cotter pin2

cotter pin eye

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