Anthony, if you read threads about "loaded tires" you'll find all kinds of things added for that purpose; calcium chloride, which is corrosive, "Rim Guard" which is a beet juice, windshield washer fluid, non-toxic or RV antifreeze, regular antifreeze, which provides a rust inhibitor, or just plain water. Personally, I put 2 gallons of Prestone in each of my rear tires, then filled the rest of the way with water, but I probably wouldn't do it again because if it leaked out and any animals drank any of it, it's poison.
I've known several farmers who used plain water. You do not want to fill the tires more than 75-80% full of liquid, then add air to the proper pressure. The easiest way to do it is to buy an air water adapter. They're cheap and you can get them at Tractor Supply Co. as well as many tractor dealers. You park with the valve stem at the top (12 o'clock position), jack the wheel up just enough to take the weight off of it, removed the valve core, hook the adapter to the valve stem and to a water hose, turn on the water for a minute or less, then turn it off, open the valve on the adapter to let the air out, and repeat the procedure until you are letting water out instead of air when you open the valve. That will get you about 80% full of water. Put the valve core back in and air up the tire.
