Every vehicle on the road today encounters brake dust accumulation on their rims, the degree of which depends on the make of the vehicle and what kind of brake pad is being used. Generally the higher the quality in vehicle and brake pad the more brake dust on the rims, giving vehicles such as the Mercedes Benz and BMW a notoriously bad rap when it comes to keeping rims clean.
If the brake dust is allowed to sit on your rims for weeks or months at a time it will eat its way into the rim, causing permanent damage.
Fortunately there are things you can do to help alleviate most of the problem. Replacing the factory brake pads would be a start, with Akebono Pads receiving high marks among many enthusiasts. There are also shields available that slip in between your rim and brake caliper, although it detracts from the look of the vehicle and leads to higher brake temperatures.
A less costly method is to protect your rims with a wheel protectant, with a couple products on the market specially formulated to protect against brake dust.
One high level protectant is Rejex, which prevents stains and adhesion from road grime and brake dust by providing a thin-film polymer coating. It works very well in prevention and provides a high shine to the rims. The downside to this product is its 12 hour cure time and it is not a cleaner, just a protectant.
The easiest to use and favorite among many enthusiasts is Wheel Wax. Straight from their website reads “High temperature synthetic formula cleans and protects.” This is a wipe on, let haze, and wipe off product similar to many carnauba waxes, so the cleaning it claims needs to be minimal. The rims should first be hosed off and cleaned with a high quality wheel cleaner first. This product is also heat treated for the long haul, meaning it will not break down from the natural heat the wheels expel during normal driving. Once this product is applied simply washing your wheels once a week will keep brake dust and road grime from adhering to the surface.
Carnauba waxes should be completely avoided. They often trap brake dust and allow it to etch into the rim.
