Originally Posted by
HillRider
I assume the 105 rings have a more textured surface, maybe bead blasted instead of polished, that tends to hold dirt more firmly. There is no way the choice of alloy could cause that problem.
Ah; I wasn't thinking the alloy would be the issue. More wondering if the color difference implied the surface of Ultegra had been coated with something (analogous to teflon nonstick pan) whereas 105 had not. But textured surface perhaps is the explanation.