A tip for those who haven't already thought of this. I have not seen this method discussed on the forum. This afternnon I filled the tires on my 8N with -30 used antifreeze I got from a local tractor repair shop. I had acquired a portable tank type pressurized sand blaster which didn't work for the intended purpose, so I changed the hose end to a male garden hose coupling, filled the tank (7 gals) with the ballast, pressured the tank to 8 pounds and attached the quick fill ballast attachment I got from Gemplers, opened the valve and it worked flawlessly. Had to refill the tank 3 + times. Slow but inexpensive.