I have an old Coats air powered tire changer in my lower garage, I'd have to look at it to see what model it is, I don't remember, haven't used it in probably 10 years. The last time I used it, it still broke the beads fine (up to 16" wheels), but it had enough air leaks the bar that turned to remove and install the tires was getting pretty weak.

The last 10 years I haven't changed enough tires on wheels to make it worth the effort to repair (or fight with) the old machine. Some local guys the run demo derby cars tell me every year they want to buy my old machine for $50, but they haven't showed up wit the money yet.