Replacing brake rotors

BGMTB
BGMTB 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.

Comments

  • 898kor
    898kor 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
  • 898kor
    898kor 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
  • cooldad
    cooldad 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
  • swod1
    swod1 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_sordy
    steve_sordy Posts: 2,443
    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 Rookie
    The Rookie Posts: 27,812
    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.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • steve_sordy
    steve_sordy Posts: 2,443
    Picky, we knew what was meant. :)

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