warning warning - cheap casters
I'm now paying the price for cheap casters on my dollies. The mover's dollies I bought at home depot for about $25 each seem to sieze up more than they roll. The casters wedge in a direction (never the desired direction) and it's near impossible to get them straightened out.
The only dolly that works like a dream is the one I built for the backhoe. I bought heavy duty casters to carry the weight, and they have two ball bearing races so they rotate and roll with ease. They were around $25 each which hurts, but they work. I can literally give the BH a light shove and it will roll across the barn in a straight line.
As a first measure, I'm going to try using two of the cheap dollies for each implement on the theory that less weight on each wheel will reduce the binding. Last resort will be to buy the expensive casters. My fuel barrel rolls around pretty well which indicates that lighter loading works.