FYI, the bigger your tires are, the flatter the tires can get in cold weather. When it's cold the air molecules move slower and they take up less space than they do when the air is warm. If the pressure gets low enough then you can develop an air leak around the rim, then the problem is even worse. And if you have your tires filled with Rim Guard, like me, then it can get expensive if enough of it leaks out. So check on your tractor every day or two.