I use a 44x17. I'm a spinner. I live in an area with short hills. For rides west, on weekends, where I open it up a bit, and where the hills are infrequent, a 44x16 is better. I ride brakeless, and have one knee that is just ok, so the small gear allows me to accelerate quickly, stop quickly, get over the hills, and not burn myself on my long commute, so it helps me to pace myself. Also trains my pedalstroke for road racing.