Originally Posted by brianappleby

Chris can you explain how black things are better at radiating than white or silver ones? I'm halfway to a PhD in physics and I haven't heard that one yet.

Back on the physics kick though... deeper Al rims will have more surface area than shallow ones, and will thus radiate heat better.

Also, stay away from flimsy plastic rim strips like these. I've melted some on the hills outside of san francisco and it makes for a long walk home. They get hot and shrivel up and your tube punctures on the exposed holes in the rim. Haven't had any problems with cloth ones or the thick sturdy plastic ones.

EDIT: Upon a quick internet search, Chris is right.: Kirchhoff's law of radiation (G.R. Kirchhoff)
The emissivity of a body is equal to its absorptance at the same temperature. Yay college!