F20 Tire size

[kaw750ltd1983]

Got 2 Farmall f 20 1937 and 38 Both on 36 spoke rims
One has 13.9 36 one has none just rim left looking for the best size to put on them without breaking the bank best front size wouldn't hurt also

 

[fixerupper]

I have a 39 f20 with 36 inch rims. The previous owner widened the rims 3 inches for 14.9 tires. The rear of the tractor sits way too high with 14.9 tires in my opinion. The engine has 8000 foot overbore aluminum pistons so he must have thought he needed the extra traction to hold the extra HP. It probably came from the factory with something smaller than a 13.6 but im not up on my tire sizes to say what exact size the tire should be.