What's heavy load? I just got 6 casters with 8" steel/urethane wheels that will hold about 1,000 each. Maybe it was 1,400. I was looking at a few. All made in America. From Albion.
Have most of the catalogs for all the remaining caster companies. I've become a caster freak. Mainly Bassick and Albion, but some Faultess as well (though I've seen some Faultless imports too) I've also been to a plant where they are making casters and wheels in the USA. Also, I've become obsessed with the bearings used in caster wheels, and have a collection of catalogs for those (all made in USA).
As far as I can tell, the market for US casters is pretty strong right now. (At least at the high end -- but doesn't the high end always remain strong?) Production methods are pretty efficient. And for those markets where you need dependability and can't be f*cking around with cheap stuff (some aviation, some medical, some manufacturing and assembly line stuff), my understanding from reading trade journals and talking to guys in the field, is the future looks good for high end.
Again, I'm no expert, but I've bought a lot of Bassick and Albion lately and it's all been USA made.
I did find one holy grail of casters that I want to get from Germany, Blicklee [sp?].
PS. I'll pull my spec sheets, just for fun, and see what the heaviest Albion there is that I can find.