BobbyG

I commute ~9miles each way on pavement. My studded winter tires are 26x1.65 which is about 42mm. My rims are 1.5 inches which is about 38mm. Skinnier tires hill help your bike cut through the snow down to the pavement, or ice, as the case may be. I am good up to 3" of loose snow. Above that, my speed is too slow to make riding to work practical.

For me, the real "a-ha" moment came when I realized (thanks to bikeforums) that tire pressure was important.

I run Suomi Nokian W106's and max pressure of 65psi is good for dry pavement. 30-45psi seems to work better for icy streets. And 20-25psi for deep loose snow. But on packed snow, ~32-35psi works well for me.

FWIW, I remember watching WRC rally driving and all the teams's studded snow tires were thin. A team tech explained they wanted the cars to cut through the snow, not float on it.