For daily commuting driving in winter snow conditions, No I do not. For trail runs in the snow then yes I do air down like most of my other trail runs. Remember under inflated nad over inflated tires generate more heat and cause to tire wear issues. On the trail this isnt an issue because you are generally going slower speeds and for very short distances. But what do I know I am from So. Cal. Hopefully some of the Colorado or other "Winter States" chimes in.