So I'm pedaling along the other day on my 4 month old Trek Mondane 4.5 when without warning the rear deraileur broke and fractured the seat stay on my frame. I stopped right away and looked to see what happened. The metal that hold the lower gear had snapped off and the main body of the deraileur also had a break in it. Curious if this had happened to anyone else? I was actually taking it easy at the time it happened tooling along at around 12-13 mph on a level section of road. Am not aware of hitting anything and like I said it was totally without any warning. The LBS is filing a warranty claim for me but I'm not sure how it will turn out. Trek covers the frame but the Shimano components are covered by Shimano. I'm afraid this is going to turn into a fight between the two manufacturers. The other joker in the deck is that the bike had just been serviced by the LBS the day before. Now I did put 20 miles on it the day before and was 9.5 miles into another day's ride when the part failed. Is it possible that something was not put back together. They did disassemble and soak the cassette and chain as part of the service. I really just want to know what could have caused this too happen and am curious as to if someone else had the same kind of failure.