[kalebevans]

Looks to me like the manual says you need the narrow rims for the 4.80x4.00-8 tire size, but your pictures of the front wheel are for the wider rims like later tractors have, which would need 16x6.5-8 tires. Not necessarily bad, but not true to original. I personally like the look of the 4.80x4.00-8 tri-rib tires more than the wider tri-ribs, but it's not a deal breaker for me. Your rear rims look like a 12x7, so you'd need 8-12 or 23x8.50-12 tires, which should be pretty similar to each other. You could squeeze 23x10.5-12 tires on them, to match the wider front tires, but they'll have extra bulge to them and a little less ground contact. They might be a little wide for a furrow if you plan to pull a plow depending on your plow size as well. The other factory option for the rears that the manual mentions is 6-12, but that calls for a 12x5 rim and you might have trouble seating the bead, and it might look a little funny. There might be a picture somewhere on here where someone tried it for you to take a look at.

So in short, if you want to keep those rims, you'll want 16x6.5-8 for the front and 23x8.50-12 for the rear. That's what I'd do, anyway.