First off, I should note that I live in Alaska and I recently started commuting to work on my Surly LHT. I am contemplating winter commuting as well since the last few years have been relatively mild and the municipality has been fairly prompt in cleaning the bike trails after a snow fall.
That out of the way, I am curious if it is advisable to switch from caliper to disk brakes on the front. Considering my route is roughly five miles with some traffic involved and quite a bit of elevation changes while toting some 50-60 pounds of school supplies (in addition to my 200 pound self) I am concerned with braking ability on studded tires and sloppy/icy conditions.
Second question is how difficult is it to switch tires? I currently on Mavic A719 rims with 700x32 Panaracer Messengers and the fender are rated to take up to 40s. Can I just change out the tires or would new rims be in the equation as well?