Can get wheels through Shoup buy during parts sales for more savings. Looks like standard 6 bolt  Ag wheels.

https://www.shoupparts.com/products/hubs-spindles-wheels/wheels/

What size tires are you running now. 11Lx15 ?

Might upgrade to a heavier larger tire like a 12.5L x15 for heavier load capacity also get like a Firestone or American Farmer tire in the FI series they have higher ply ratings higher inflation rating and higher speed rating. Different wheels may be needed too. 11L tire would fit a 8" or 10" rim but a 12L would need the 10" I believe. Lot of JD equipment used same style rims just need to check center pilot holes and stud holes.

https://www.stausaonline.com/tires/american-farmer-fi-implements/

Your tire looked like my 11.5L x15 I put on a 250 bu gravity wagon. Wore the edges down rapidly because of the load. Also crowned roads take a toll on the downhill side too. I upgraded to 12.5L x15 F1 tires.

Could also go to truck tires get special wheels from Unverferth 

I got some rims from them back in the late 70's early 80's for some 7.50x16.5LT tires that were popular at the time.