It's a Firestone radial tire.  It doesn't have the size on it and I've looked a lot.

So I measured across the rim from where the bead sits to the opposite side.  It measures 42 inches.  (outside of rim to outside was 44 inches)  I looked down along side the tire and set my tape, then looked down along the opposite side and it measures 18.5 inches.

I'm assuming it's an 18.4X42

There are 4 of these on the tractor.  2 inside and 2 on duals.

What would be the proper air pressure for the inside tires and what would be the proper pressure for the dual?

Thanks.