It's almost time for

 

Is this just a dumb question or does no one know the answers? Can anyone suggest a winter tire size?

 

In my family, all has AWD type vehicles. Vehicles all have two sets of rims/tires. Winter tire is mounted on 1" smaller diameter rims to have little taller
tires. Two Bimmers, my RX, wife's Subaru Forester. I do seasonal tire/rim change myself having proper air tools, floor jack. If you use one rims, keep mounting
tires back and forth every season, there is a chance how ever small rim or tire can suffer a damage which I wouldn't like. Our favored winther tires are Michellin or Nokia.