I recently ordered hydraulic Shimano disc brakes with rotors and they came with a bunch of hardware, including this piece: enter image description here

It looks like it would fit under the screws that secure the rotor to the hub: enter image description here

Does anyone know what I should do with it or what its function is?

1 Answer 1


These things are called tightening plates or lock washers. Your suggestion was righ in where it goes, here's an exploded diagram and installed photo: enter image description here

  • It seems the OP is missing two of them then (the photo shows three) as well as the flange.
    – RoboKaren
    Apr 4, 2015 at 14:28
  • I guess he'll have to contact the seller in this case. Apr 4, 2015 at 15:41
  • These are brand new disc brakes that I installed myself. I have 6 of those pieces, 3 for each disc brake. I just wan't sure what it was, so I showed one of them in the photo. Thanks for your help! Apr 5, 2015 at 22:07
  • Can a source for the exploded view be provided? Apr 7, 2015 at 20:55
  • 2
    @LopSae Official Shimano exploded views: Rear Disc Brake. Front Disc Brake
    – Stainy
    Apr 14, 2015 at 20:05

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