The winter bike I'm building has a 34x18 but mainly because those were the parts that I have handy (It doesn't even really snow that much here)

My single speed cyclocross bike was 39x16, I switched it to 39x18 and I still felt like I couldn't spin fast enough. I would see guys on 2:1 ratio bikes having a much better time on the course but I don't want to put an MTB crank on. I've been contemplating putting on a 19 or a 20 freewheel but the other part of me just says I need to get faster and become a better runner.