My wife and I ride the same bikes (Specialized Tricross Comps) with Ultegra derailleurs. Her chain was extremely noisy and rough today going through the rear cage so I put it on the rack to see what was up. A small tab (red arrow in photo 1) was bent into the chain line and the chain was forced to roll over it. I can't see very well with my 62 YO eyes but it looked like a small section of the tab had bent away from the rest and was poking into the chain path. I got at the thing with a vice grip and something seemed to pop off and disappear (I think that was the portion intruding into the path). I squeezed the remainder of the tab into a position that looks like the tab curves in about the same as the one on my bike (red arrow in photo 2). It shifts smoothly now so I am inclined to just let it go for now and see how it does. Does anyone think there is anything to worry about? Also, is that tab intended to keep the chain from moving vertically and popping out of the intended path?
As a side issue, those pulleys look pretty gross. Do most of you periodically clean them with a small brush or does the grime not matter a lot?
Thanks for any help.