Here's the problem. I bought a new Cannondale road bike and have been testing it today. I noticed that the gearing was not set properly as the chain came of the crank set two times. I fiddled around with the adjustment screws and now have the problem that I can't screw them fully back in again. Orignally they were more or less fully screwed in and were flush with the derailleur surface. When I was playing around with the screws to get the gearing right again, I suddenly noticed that I could no longer screw them back in again. They only go half way and then stop. Any idea what the problem could be?