Assembled wheels into tires. Ran 1/16 in. bead of Permatex Ultra Grey (82194) high torque gasket maker around the face of one side of the wheel assembly to ensure no leakage between wheel halves. Placed lower wheel on 2x4 wood blocks under tire. Placed upper wheel half onto lower and bolted tight with all six bolts. Then placed the rubber o-ring at the wheel join. Used a lot of watery dish soap as lubricant during tire inflation, used ratchet strap to compress center of tire during inflation to seat bead onto rim.
Gear installation preceded tire / wheel assembly.