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  1. #1
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    Polishing Disc Brake Surface?

    I was just curious...

    I bought a used specialized hardrock with disc brakes, and the rear brake surface on one side seems very rough (maybe they didn't change the pad?).

    Could I take my polishing wheel on my dremel and smooth it out again? Sorta like turning a car disc brake?

    I don't have alota cash to buy a new disc, so is this a viable alternative?

  2. #2
    Meh.
    Reputation: XSL_WiLL's Avatar
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    Smooth = lower friction coefficient

    Brakes = all about friction.

    Take a picture. Most likely, leave it be.

  3. #3
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    If it's not burred, then leave it. If you need to do anything to a rotor, the best thing one can do is a circular pattern with a wirewheel, which will leave a "nondirectional" crosshatch pattern, like cylinder honing.

  4. #4
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    Quote Originally Posted by nwjmtnbkr
    I was just curious...

    I bought a used specialized hardrock with disc brakes, and the rear brake surface on one side seems very rough (maybe they didn't change the pad?).

    Could I take my polishing wheel on my dremel and smooth it out again? Sorta like turning a car disc brake?

    I don't have alota cash to buy a new disc, so is this a viable alternative?
    using a hand dremel tool is NOT analogous to turning an auto rotor.

    at best, you might be able to wet sand using a large piece of fine paper on a flat surface...like a glass table. use circular motion to obtain a cross hatch finish as mentioned above.

    HOWEVER, rotors are, i'm assuming, hardened steel. i don't think it will do much.

  5. #5
    Meh.
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    It'll scuff up the surface some, and that's about it.

    If you look at new rotors, you'll see that the surface is not smooth. Since he's got a cable actuated one piston brake, that means that one pad is static and one is dynamic. The dynamic pads pushes on the rotor and flexes it into the static pad. This could explain why one side of the rotor shows more wear than the other. I've certainly seen it before.

  6. #6
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    Quote Originally Posted by XSL_WiLL
    It'll scuff up the surface some, and that's about it.

    If you look at new rotors, you'll see that the surface is not smooth. Since he's got a cable actuated one piston brake, that means that one pad is static and one is dynamic. The dynamic pads pushes on the rotor and flexes it into the static pad. This could explain why one side of the rotor shows more wear than the other. I've certainly seen it before.
    boils down to the simple fact he needs a new rotor. bike rotors are not made to be fixed. they are made to throw away.

    as i think someone already mentioned above, his best option is to buy new pads and let them bed into the bad rotor. i don't see why they shouldn't suffice for the time being. it's not a formula 1 race car.


  7. #7
    Meh.
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    But I don't think that he DOES need a new rotor.

  8. #8
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    Quote Originally Posted by XSL_WiLL
    But I don't think that he DOES need a new rotor.
    i take back what i said and agree with you based on these two facts:

    1) fact that it is only a bicycle

    2) fact that he asked this question on a forum would leave me to believe he could not "out ride" the rotor's useful life

    **nor do i believe it is a safety issue if the bike is used as intended.**

    to OP, go ride and have fun with your new bike and don't worry about brakes unless it really is not doing it's job

  9. #9
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    I don't see it as needing a new rotor and I agree with Will that it is likely a single moving pad issue that is adding to it.

    For myself, I used some fine emery paper and a figure 8 pattern to get things cleaned up a bit and keep the good braking force.
    As if four times wasn't enough-> Psycho Mike's 2013 Ride to Conquer Cancer Page

    Moran? Let your opinion be free -> F88me

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