I'm bidding on a three wheeled recumbent for this winter. Last winter I used a 20 inch tire city bike, seat lowered so that I could easily walk my bike if I needed to without dismounting. I was really suprised how well normal city tires did in slush and light to medium snow. Luckily snow only lasts an afternoon here in the Netherlands. The rain melts it off. We only had 6 or 7 days of so called "bad" snow here. (Im originally from Indiana, so I laugh at what the Dutch call snow)