Treat the snow as clean cold mud. I have run long commute(12mi) for 2 winters (3.5k miles)with my marzocchi Z-4 air fork and Manitou black with no complaints at all. One of my earlier mods to it was to add the accordion rubber boots(I know, hang the style nut [rolleyes] To compensate for the chill I do usually turn the rebound to full open. Lube your chain with something closer to the motor oil side of the spectrum, such as Pedros Wet. It provides enough of a residue to lessen the packup, with the caveat that you will have to clean it a little more often. But hey, thats why I prefer to buy chains in spring
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So far as tires go, treat it like you are going to ride in wet clay. Something with open yet deep blocks that clear themselves. Spikes/studs help in the ice, but I have yet to actually buy some, if thats any indication.