Ya, I know, retreads; how pathetic! But I love them. In deep snow, other rigs with bigger tires rarely do better than mine. And, on packed snow/ice I haven't seen another mud tire that does as well. But, last weekend I destroyed one of my tires. I'm using this as an excuse to go to larger tires (315/75R16).
Now I've always suspected that tire compound and siping are what get you through snow, even deep snow. Note that the "Kedge Grip" in my current tires is crushed glass and crushed walnut shell molded into the rubber. According to Treadwright it "acts in a twofold way; first the walnut shell is designed to come out leaving small (approximately 1 mm) size pits in the tread surface that will act as additional siping and create more traction edges to grip the road. The second is the crushed glass which is designed to stay in longer and create a gritty surface to help anchor you to the road."
If they were available, I'd buy another set of Tredwright tires, but the size I want is basically on back-order. Since my spare tire is smaller than my other tires, I need tires now for the snow season. So, based on my theory that the rubber compound and siping are the most important, I'm really tempted to get Yokohama Geolandar I/T GO72 tires.
Note that while I drive my rig on the highway to get to the snow, basically I only drive it when going snow wheeling. Thus, while I need DOT approved tires, performance in deep snow is most important. Noise and on-road behavior are of minor concern.
So, convince me that lugs, such as on a mud tire, are important in deep snow - that they do more than dig you into a hole faster.
I could move the tires further outboard with spacers or rims with a different offset, but this might make them rub on the front edge of the fender.
