Bought a zd221/54 today and love it. Rides a little rough on my yard, but my yard is real rough. I also suspect the tires have a little too much air in them. Super smooth engine, deck engagement, etc. etc.
My dealer told me they come completely assembled. If there was a tire out of round I suspect that to be the tire mfg's fault.........or something like that. Any other problems you saw or just the tire?