I know I am late to the party, but I recently replaced my 16" tires with 19.5 G rated Boar Wheels and Tires. Bolt right on. They are relatively inexpensive. Numerous cattle ranchers and industrial haulers around here do not have the time or patience to put up with blow outs, so many are switching to this tire/wheel combination in lieu of carrying 2 or 3 spare tires. And if you have ever followed one on the freeway they pull in excess of 70+ MPH.
The tires ARE made in China. However you should look at them compared to regular trailer tires. Their sidewall is extremely thick and rigid and lower profile so the tires do not "flex" when they turn, so much as "skid." They are rated for 70,000 miles and can be retread. I believe there is a Youtube video out there somewhere.
Those same cattle ranchers mentioned started putting them on their 5th wheels with great success. 110 PSI just about maxes by air compressor.
I noticed an increased smoothness in pulling that is difficult to fully describe, but so far, so good. If I ever have any problems with them I will post it to this forum.