I don’t know about Uniroyals, but If you’re looking at clearance issues there’s a decent selection of 225-255/60/15 tires out there for great prices and a 60 series would increase clearance a bit
Clearance shouldn't be the issue. I'm more concerned with putting too wide a tire on too narrow of a wheel. Go too wide and the beads become "sucked in" and the sidewalls warped/sloped and unstable. 245 is the maximum width for 8 inch wheels (I believe)