Originally Posted by
shecky
This is interesting. I'm not familiar with the whys of coating rims with ceramic, but it seems that ceramics are better insulators than bare aluminum, and as such dissipate heat less efficiently. As a result, friction heat is concentrated in the braking surfaces. This would seem to contribute to cause increased pad wear, as higher heat translates into softening pad material. This behavior is associated with brake pads on steel rims.
As far as I've read/been told, the reasons for ceramic coating rims is to improve braking performance, particularly in wet/muddy conditions and to make the rim more resistant to wear. In my experience, the braking part is true. The downside is, of course, that the increased coefficient of friction between the braking surface and the pad
devours conventional pads.
That said, though, there aren't that many rims nowadays that rely on ceramic coating. Ambrosio is the only brand I can think of that does it widely throughout their range. Mavic does it as well in two models.
Improvements in metallurgy, brake pad compounds and the machining of brake surfaces have reduced the need for the coating.