As you can see in the photo below studded tires and enough layers let me ride all year long. This was taken last winter. The temperature leaving the house on this ride was 8 degrees F. I had six layers up top and three on the bottom. Walking was more cumbersome than riding. It was cold enough that morning that I even put a helmet cover on in addition to the balaclava. I probably had more layers on for this ride because I knew I was going to stop and take photos along the way. In any event, with that many layers there is no such thing as an aerodynamic position on the bike. However, even with the slower rides the effort seems to remain the same.