I have a problem with ghost shifting on my front chain rings. I recently broke my old chain and decided to put a new Sram chain on. Everything works fine except for when I have the chain in the middle ring. It keeps jumping off to the lower ring or all the way off very violently when I apply pressure to it such as when i am climbing or putting the hammer down. Again it will not do this in the other chain rings, and it is not rubbing against the front derailer. It sounds like I might have a problem with the middle ring, but I can not see anything wrong with it visually. Any suggestions?