I just bought a set of SRAM s80's for my tri bike....I'd like to keep my stock wheels on for training and switch out the s80's for racing. To make the change simple, I am going to buy a new cassette to put on the s80 rear. My current cassette is 11-23. Is there a problem w/ buying a 12-25 for the s80, or should I stick w/ buying another 11-23? Are there advantages with a 12-25?