Originally Posted by PaulRivers

Well - there are a certain number of people who have no problem falling over a couple of times a year on their bike. And if you ride regularly without studs in the winter, you WILL fall on your ass a couple of times when you front tire hits some ice and goes down like a piano onto Wille Coyote.

I am not one of those people though, and for me (and the advice I give out) I would say the #1 thing you need for winter biking is a good pair of studded tires. Schwalbe and Nokian both make good stuff. Studded tires don't come in sizes below 35c (technically one set does, but it's a little lacking in the "number of studs" department and I haven't heard the best things about those ones on ice, so let's say 35c).

So I'd say tire clearance would be my #1 criteria. There are other, bigger studded tires as well for worse winter conditions so the more clearance the better.

In my opinion, I don't agree that front suspension is needed. Most people who winter bike (most, not all) do so without any extra suspension.

Single speeds are actually fairly popular though, as if you grit up the chain and drivetrain with road sand and salt all winter, you can replace the whole chain and cog pretty cheap. It's a matter of opinion though - winter riding can make you wish you had gears even more as additional snow can change your pedalling speed kinda dramatically, even though you're on the exact same route.

I would say a "hybrid" (basically a mountain bike style bike, but with no suspension) is probably the most common bike for winter biking, followed by cyclocross bikes (because of their bigger tire clearance).