Has anyone exceeded the recommended max tooth capactiy for a rear derailler? I have an Ultegra rear derailler which has a max tooth capacity of 27T. I was thinking about ordering a new cassette that has the largest cog at 30T. Just wondering if it is possible or if this is a bad idea. Anyone tried this or know if this is ok? I mean, what's the worst that could happen if it doesn't work?