I finally got a chance to trail ride on one of the new fat-tire trail bikes, thanks to my buddy Phil who bought one last fall (his is similar to the one in the pic). We took off onto our Almonte Riverside Trail this afternoon in the midst of snow squalls and biting wind, over a mostly packed snow surface hiding postholes and icy stretches. Phil gamely rode his 26" dually with studded tires while I practically cruised along on 5 psi balloons.
If you haven't tried one of these bikes, I highly recommend it. The contact patch has to be around 48 sq in, which means you can float over almost anything like you're on suspension and find traction in the most ridiculous circumstances. For instance, this was the first time I'd ever managed to pull a burnout on a bike. I just pedaled like mad in circle on undisturbed snow, and carved an awesome lazy donut--complete with roost. Serious giggle factor. No motor needed for this kind of hooliganism.
The trail has some steep twisty sections that were completely eaten up by this thing. Cornering was a little weird at first, but once you get used to the side-slip you look for little berms to bounce off of and trust that the massive contact patch with its little knobs will snuffle out and engulf any tiny features offering traction under the snow. It was almost as easy as riding in the summer.
A bike like this opens up a whole new season for knobby fun when skiing conditions suck, there's not enough snow for snowshoeing and too much for trail running, and you don't want to take a bike on the roads because of the salt. Definitely on my list for next bike to buy.
Update: Rode the same sections on 26" duallie today with tires at 25 psi. Snow was hard frozen so it was surprisingly good to ride. Managed to do almost everything without dabbing, but icy sections were sudden death because I didn't have studs.
Edit: Contact patch size.