Originally Posted by
calamarichris
If it's a major concern and you don't already have them, you might also consider getting black rims.
According to Kirchhof's Laws of Thermodynamics, dark surfaces are more apt at absorbing and radiating heat away. The black rims will of course feel hotter to the touch, but that's because they're doing their job.
It's the same reason the bottom of the space shuttle and the backs of most refrigerators are black.
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!