So true. I've drove through mud with my tractor. It was deep enough that it was basically plowing the mud with the front axle. The tractor kept on going without any issues and I don't even have R1 radials.
A couple days ago, a video popped up on Facebook where two compact 35hp tractors with R4s were struggling so hard to pull a trailer stuck in mud. The first thought that came to my mind was: "Man, two tractors with R4 aren't worth a single one with R1." Those things spin if you look at it the wrong way.