I got my 53 LeChamp Ti Heat last week and did 100+ miles over the weekend. I was worried when I finally heard back from BD that they would recommend 49 for my height of 5'7" with 30" inseam. I waited for a few day to get their recommendation but they are slow to reply. I had already placed my order couple days before getting their size recommendation. I want to get the bike and myself ready for the upcoming MS150 ride. I thought with lots of research on bike sizing and my current bike is a 55 steel Serotta that ordering a 53 LeChamp Ti Heat should be pretty safe. I was so worried and wondering if I should even bother opening up the package. I did and found that the size was similar to my Serotta but a little smiliar. Fit me perfectly. It's a very personal thing - the bike fitting. We are taking a risk ordering it online with a killer price without actually fitting it. I think you should be OK with 53. But, if you have to time to wait, why not? The top of seat is still slightly higher than the handle bar which is the position I like to ride on. Not with the seat post all the way up. BTW, I am 44. Riding on a bigger frame is more comfortable. Again, it's a personal preference. I did not even know this forum before I ordered my bike to get advice. My steel Serotta has a full Ultegra. Now with the SRAM Rival on the Heat I can get a sense of extra saving vs. quality difference. It's a good set but my personal opinion is that Ultegra has a slightly better quality. The Aksium wheels are quite heavy but I have no complaint since I did not pay much for the complete bike. Will replace the wheels when I get a raise next time.