Thanks to everyone for their input. I am worried about stability and have had the wheels come off of the ground while working. I ordered a single bottom plow and in the user manual it wants the rear tires to be the same distance from the tractor center line as the front tires for proper plowing. The right side wheels will be down in the furrow while making the next pass. I am running R4 tires filled with liquid. 2 inches will bring the inside rubber the same distance from the center line as the front tires. 3 inches would be a bonus but at what point do you start to stress the wheel bearings with the extensions?