I'm currently using a 50-34 FSA crankset (9-speed) with an 11-23 Sram cassette. I've seen on IRD's website that they have an 11-28 cassette which they claim is a good match with compact cranks. I'm considering switching over to it for a couple of extra lower gears for climbling. They also have an 11-25 which is a possibility. Does anyone have any experience with the 11-28? Would I have to use a triple rear derailleur with it?