Lets talk about the diff between 19.5 and 22.5's on Gassers

I would think that the 22.5s have a higher weight capacity, but that's ultimately going to be limited by your chassis rating. I would also think that the larger tires would ride significantly better and may wear a little better. As for converting them, there is probably an adapter that would need to be used to attach to the hubs. With that alone, I would NOT want to convert. Anything that needs an adapter becomes a weak point.