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Brake pads for a rim brake are usually treated with Carbon Black (powered carbon) to make them last longer. This is what makes them black.

When I ride a road bike in hilly areas, the carbon black accumulates on the rim and on areas surrounding the brake pads. Later, if I ride the bike in the rain (without fenders), this powder mixes with dirty water kicked up by the wheels, and spreads around on the frame of the bike, and into gaps on the headset and bottom bracket. If allowed to dry, it becomes extremely difficult to remove.

Right now I remove as much as I can with elbow grease, and then make an abrasive paste out of water and baking soda. The paste works pretty well, but leaves a residue. Further, on some of the really bad stains, it seems to spread out the carbon as much as clean it off. It still needs a lot of rubbing.

Is there a standard cleaner in which carbon black is soluble? Is there a better way to remove it?

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    Car wheel cleaner. It is made to deal with brake dust. – paparazzo Aug 27 '14 at 18:57
  • I feel like there's something else going on here or the black paste you're fighting isn't brake dust. I've never been unable to remove brake dust with elbow grease. – Scott Hillson Aug 27 '14 at 19:22
  • @hillsons since it only seems to be a problem after the rain, it's possible that some mud or other debris are getting mixed into it as well. However, I'm reasonably confident that the main ingredient is brake dust. – John Doucette Aug 27 '14 at 22:38
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    I regularly clean my rims with kitchen soap and a dish and cookware washing pad (the green ones that are roughly 4"x6"). If I do it soon enough it doesnt require much scuffing and avoids this black paste buildup. – Jahaziel Aug 28 '14 at 19:56
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    The smoother the surface, the easier it should be to clean. Very rough powder coats can be a major pita in this respect. – arne Aug 29 '14 at 8:01
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The usual cleaners for rims are:

  • citrus cleaner

  • simple green

  • isopropanol (rubbing alcohol)

  • dish soap and water

You may want to try them on your frame.

Also, you may want to try a different type of brake pad to see if they reduce the dust (e.g. kool stop salmons).

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Since no answers I will post my comment as an answer

Car wheel cleaner. It is made to deal with brake dust.

But I would not user car wheel cleaner on paint.
For hard to clean on paint I use a cleaner wax.

  • Car wheel cleaner would be great for brake dust from a car. Cars use disc brakes with ceramic or steel pads on a steel rotor. The brake dust that the OP is talking about is carbon black from rubber brake pads. These are completely different materials. Also, I would hesitate to use car wheel cleaner on my rims as it may affect the braking performance and the pads as the cleaner will get transferred to the pads. – Kibbee Aug 28 '14 at 19:59

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