I mount all my tires with a bench mounted manual tire changer I bought at Northern Tool for less than $50.00
Lots of dish soap to mount and then you take the valve out of the stem and put a strap on the tire, use a air blow gun to push lots of air in to seat the bead to the lip of the wheel, put the valve back in and fill to desired PSI.
For 8" wheels I always tube them.