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Replacing brake rotors

BGMTBBGMTB Posts: 2
edited October 2018 in MTB workshop & tech
My rear brake rotor is blueish purple should I replace it or try cleaning and or sanding the rotor first. It a fully stainless steel shimano rotor and the brakes are shimano m506.

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  • 898kor898kor Posts: 81
    BGMTB wrote:
    My rear brake rotor is blueish purple should I replace it or try cleaning and or sanding the rotor first. It a fully stainless steel shimano rotor and the brakes are shimano m506.

    Good effort :D

    I did the same with my M506 also, so I fitted the radiator fins from uberbike and noticed a dramatic increase in braking power, a big reduction in heat generation and subsequently and no further discolouration.
    Bossnut V2
    Levo FSR Comp
  • 898kor898kor Posts: 81
    898kor wrote:
    BGMTB wrote:
    My rear brake rotor is blueish purple should I replace it or try cleaning and or sanding the rotor first. It a fully stainless steel shimano rotor and the brakes are shimano m506.

    Good effort :D

    Im assuming you have overheated the brakes recently?

    I did the same with my M506 also, whilst they were fine, the fact that they are discoloured means they have had their mettalic properties changed so I fitted the radiator fins from uberbike and noticed a dramatic increase in braking power, a big reduction in heat generation and subsequently no further discolouration.

    Have you checked your pads for glazing? They might recover with some emery cloth but might need new. What compound?
    I found my weight cooked normal organic compounds but a mixed compound from Gorilla brakes works very well.
    Bossnut V2
    Levo FSR Comp
  • cooldadcooldad Posts: 32,599
    You don't mention braking performance. If it works fine leave it. 99.987654677% of brake issues are caused by unnecessary faffing.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

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    Parktools
  • swod1swod1 Posts: 1,639
    Yes if the brakes work and there’s no squealing noise just leave it.

    Are you using metal pads?

    Could be the disc is only suitable for resin organic brake pads.
  • steve_sordysteve_sordy Posts: 2,417
    The colouration just means that you got the brake disc hot enough for the metal to oxidise. If I could remember far enough back I could tell you how hot they got from which colour. The thing to watch for on brake discs is the thickness. The minimum thickness should be engraved on the disc, close to the arms or maybe even on one of the arms. You then need to measure it though and not everyone has a micrometer; vernier calipers are unsuitable for the job.
  • The RookieThe Rookie Posts: 27,809
    898kor wrote:
    a big reduction in heat generation and subsequently and no further discolouration.
    A big reduction in heat generation comes only from braking less..... I presume you mean a reduction in heat build.
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • steve_sordysteve_sordy Posts: 2,417
    Picky, we knew what was meant. :)
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