My Nebulous Theories

Rough (Aluminum) Rims?

Have you ever noticed after a hard and/or long brake that your rim brakes seem rougher? My nebulous theory is that Aluminum's natural tendency to stick to things builds an Aluminum coating on the brake pads. Then, when the Aluminum coating is thick enough to be affected by shear and/or torque, it crumbles, or it is scraped off of the pads in tiny shards.

Those things alone wouldn't be so bad, but then the Aluminum wants to stick to itself again, because of course, Aluminum likes itself so much. Some of the lost Aluminum rejoins the rim, and when it does it makes a rough and convoluted surface. The other thing that seems to happen is that the shards tumble and roll as they are trapped between the brake pads and the rim, and eventually some of those shards embed themselves in the brake pads.

And of course, rim brakes will wear your anodizing off whereas disc brakes will not.