Riding in the snow is my favorite and I cannot wait until the arrival of winter. In the last year or so, I have been fortunate to ride in many, many different places from Colorado and Wyoming to Italy and Switzerland, but my most memorable moments on the bike occurred closer to home, in Putnam County, New York on snow-covered trails and hardpack roads.
With the proper equipment, riding in the snow makes for outstanding off-season training. I ride a full-suspension mountain bike with 2.3 inch studded snow tires on wide rims. I am about to purchase ultra-wide Snow Cat rims to effectively increase contact area.
With my current configuration, I had little trouble riding in snow up to 6 inches deep. Ice is no problem, but one must be careful to balance the required tire pressure. Snow requires very low pressure, while if the pressure is too low, stud grip on ice will be compromised. I am considering the tedious option of making my own 3" studded tires, but first I will see how much extra traction I gain from the Snow Cat rims.
Keeping warm is not a problem; I generally have the opposite problem, keeping cool on some of the moderately long climbs we encounter. 50 pounds of bicycling and winter clothing with a snow surface can turn a 20 minute climb into a hour-long one. Therefore, modulating your effort is key. We try not to go too, too hard when climbing and keep the effort up on descents and flats -- easy, as in deep snow descending can be as much work as climbing.
Keeping your feet warm is a must. I use Lake winter mountain bike shoes, wools socks with a chemical warmer. Make sure your shoes are a size or two too large.
Here is a video:
http://www.youtube.com/watch?v=u8E_I_vh2Q4 the further into the ride, the deeper the snow gets!
Winter riding also opens up trail possibilities that you would not consider during the summer...
John979 AKA SnowLeopardNYC