I've run the 27" ITP 589/MS on my Grizz since '02. I plow lots of snow on both gravel and asphalt. Don't need the studs at all. They mark asphalt when spun and provide terrible grip on wet asphalt when there is no ice. Prior to that I ran Goodyear MudRunners on my Sportsman for 3 years. IMHO the 589 grip much better and do in fact dig down, which is just what you want in a snow environment. I've run easily in 2'+ snow even with my plow mount hardware still on with no problems at all.

 

Take a look at the goodyear mud trackers.

 

I have 589's on my grizzly and they really do dig into anything. They are not the best for powder. They are also very stiff and really fatigue you when trail riding. Im only going to use them in the winter and spring when it is very muddy. Right now i am in search of a great all around tire.

 

Mudlites are excellent in the snow.