I'm currently running a 50/34 with an 11-28 (105) on one of my bikes. On long, gradual descents I find that I'm starting to spin out, so I'm toying with the idea of swapping over to a 52/36. If I swap to a semi-compact, should I also swap the cassette to an 11-30 to keep the lowest gear relatively similar? The area where I live is hilly, not mountainous, however. Mostly rolling, with several 3 and 4 category climbs dotted around, but I don't think anything much bigger than that. Advantages and/or disadvantages to making the swap? If I swap, should I keep the 11-28 on the back and see how I get on?