Originally Posted by Portis
Studded SNOW tires really don't exist. Well, actually they do but they aren't designed for snow, they are designed for ice, it is the studs that are necessary on ice, but not on snow. YOu can find much more agressively treaded tires for snow, which is what you want.
Now I have to disagree with you a bit. I think that the wider studded knobbies (like nokian 240) really are designed for snow. Why else would there be knobs on the tires? Studs don't help much in loose snow, but they certainly don't do any harm either.
What kind of a tire is the best in loose snow? The really most vital thing for a snow tire is width. The wider the tire the better. The knobs have to be far apart, because if the knobs are too close together they will fill up with snow. So the ideal snow tire is really wide with aggressive knobs that are far apart (no studs needed). But still I think that the studded knobbies are designed for snow. Snow and ice!
Giving someone advise on tires for winter is very difficult, since no tire is the best in all conditions, it's all about trade offs. But one thing is for sure, nothing performs as good on ice as studs.
My advise is that you can bike most winterdays on knobbies, or alternate between knobbies and slicks if you like. But I can not recommend that you ride knobbies on icy days, either get studded tires or rest the days that are icy. If you ride knobbies on icy days, deflate them to really low pressure (for maximum contact surface) and be extreemely careful.