So here's something about Shimano chainrings that I am wondering. My bikes have generally had either ulegra rings or whatever rings came with my Truvativ cranks. My wife has 105 cranks/rings. When cleaning rings, I often noticed that the dirt was harder to get off my wife's rings -- usually needed at least water to get em clean whereas I could wipe most dirt off my rings with a dry rag. Recently I needed to replace one of my truvativ rings and found a cheap 105 53t ring, so I used that. Same deal, takes a bit effort to get dirt off the 105 rings as compared to the ultegra and truvative rings I use/used. So what explains my experience. Are 105 rings coated or not coated with something that makes em stickier? If it matters, 105 rings are a different color (light silver) than Ultegra 6500 rings (more of a flat gray).