I'm 5'5" and I've had the 15 and the 17" fx. I think the 17" fits the best, but I really think I'm between sizes. I went with the 100mm stem on the 15" and 90mm on the 17". The fx is a hybrid, so the fit is more forgiving than a road bike. Maybe the fx isn't for you? Did you try a 17", because I think it sounds way to big.