For every change of 10 degrees Fahrenheit in air temperature, a tire's inflation pressure can change by about one psi, (pounds per square inch). That means in our bitter cold, there could be big changes.

"Proper inflation helps drivers avoid uneven wear and tire sidewall damage in extreme low pressure situations. Maintaining sufficient air pressure is required if your tires are going to provide the handling, traction and durability of which they're capable," say the folks at tirerack.com.

Some people say they are having a hard time finding gas stations that have working air pumps. Has this been your experience? Let the Drive know. Email drive@startribune, leave a comment here or tweet@stribdrive.