I've been talking to the guy at the bikestore, and he used to have one of these bikes for 18 months. He had no idea why this happens. His was setup exactly like mine, except he had dorados. So the rear triangle or chainline are probably not the reason. The fireroad is very simple, so it didn't bottom out, and it had just come back from a service and had no falls on it. But I hope that this new derailleur will work.