Choices for replacement die cart wheels?

We're replacing swivel caster wheels on some die carts we want to load up to about 2500 lb. contents each, carts weigh 350 so total load should always be under 3K lbs spread onto the four swivel-casters. Present wheels are Albion 6" x 2" with non-wheel parts just like this one in photo below. Old wheels are grey plastic wheels having thick red plastic tire. Those tires are either missing chunks or have many cracks and will soon be missing chunks, so we want to replace all 16 wheels on the 4 carts. Those wheels were never loaded much, think they are failing from old age. Have bought some smaller wheels for other carts from "Accord" which has good selection and prices, so have been looking at their 6" x 2" rated at 1200 lb. load. Price is a key factor. We're looking at either cast-iron only wheels or urethane tire on cast-iron wheel, either of which are under $19. Each. Is there anything special I need to know or watch out for in ordering a bunch of caster wheels, or do I just proceed relying on sellers' performance data and get this done? BTW shop floor is thick concrete and other cast iron caster wheels are already used on it.

Make sure the wheel bore and bearing type is compatible with your existing hardware.
Might doublecheck the actual width of the wheel with the vendor, to ensure a good fit with your existing hardware.

Thanks. It seems like most wheels say from 4 thru 6" anyway, 2" wide, have standardized on accommodating a 1/2" axle of a certain length. I haven't looked at other sources yet but Accord is this way. The 6x2 wheels arrived and look pretty good, will put in casters soon and if all looks good will order several more sets. Yes they are made in China but I can't afford to pay a few times the China price for US products that aren't going to perform any better. I pulled the bearing sleeve out of one to show it. The sleeve rotates inside of a roller bearing with about a dozen roller pins nearly the length of the hub. The bearings came pre-greased. Again, these are urethane on cast iron, advertised load capability is 1200 lbs.

Just keep in mind, on 4 wheels, unless your floor is perfectly flat, any wheel could have half the total weight.

Was going to point that out, but he went for more than the absolute minimum load rating, and the urethane tires will provide some compliance to deal with small non-flatness. I did expect slightly thicker tires, though.