Originally Posted by PaulRivers

As everyone has said, carbide studs are a requirement as the tire will wear out before the studs (you don't suddenly fall over when the studs wear out all of a sudden).

I use Schwalbe Marathon winters. One year, I thought I'd buy the Nokian 29(something's) - their 26" heavily studded, heavily knobby tire. To be fair, my Marathon Winters were 700c while the Nokian was only 26" (I put it on my mountain bike).

I was kind of shocked to find that in riding in a snowfall, there was no difference between the 2 tires in their ability to handle deep snow. Anything the Schwalbe could get through the Nokian could get through, anything the Schwalbe got stuck in the Nokian got stuck in as well. There was this one stretch of uncleared sidewalk - only made it halfway through with the Nokian. Walked back to the beginning, got the bike up to speed, plowed through the whole thing as long as I was going fast. Figured no way would the Schwalbe make it through. Came back with the Schwalbe - it handled it exactly the same, couldn't make it through going slow but plowed through it going fast.

My side-by-side never dealt with icy ruts, but with snow - they're basically the same. Except the fatter Nokian was way more work to pedal.

Only tire I've found that handles snow **significantly** better than the Schwalbe Marathon winter is an actual fatbike tire.

One of the great things about the Schwalbe Marathon winter, to, is that you can change the stud contact by changing the tire pressure. When it's nasty out I ride with low pressure, and all 4 rows of studs come into contact with the ground. When it's relatively nice out - like in the fall or spring where there's only occassional ice patches (or when the MUP is well cleared) - I use a high pressure, which causes only the 2 middle rows of studs to come into contact with the ground, and the bike rolls faster.