Thank you for all the information. I fitted up a 52 tooth chainring and its closer. The cage is probably still a couple of mm away from clearing the big chain ring. The radius of the cage looks fine against the big chainring. I'm thinking this der. is for a compact crankset. I think a 50 tooth chainring would allow the cage to clear? If the der. says "racing triple" will it work with a 53 tooth outer chainring? Thanks again, Andy