I believe that is by definition, as used when talking about tractors.
But really, all things considered, does it really make any difference in operation of the tractor at the tire contact patch, if the wheels/tires are different diameters or not? I don’t think so, except that larger diameter tires on the front are probably better than smaller ones.
Actually, I see the answer when I look at my tractors. They both have OEM 4WD decals on them! The manufacturer should know what he built and sold, right? My tractors are 4WD!
So it has now been proven that my FWA tractors are REALLY 4WD tractors!
I’ll sleep better tonight! ROFL...