I have never seen chains of a tractor! However, I have stuck a small (32 hp) 4WD tractor twice in the mud while trying to bush hog the edges of my marshy areas.
Both times when I was getting pulled out, I could hear the massive suction on the sidewalls of the tractor tires finally break as the tractor got back on top of the ground.
I wonder if one way the chains help is to prevent all of the suction when the tractor tires do deeply sink into saturated ground?
They not only help break suction, they multiply traction over just where there is weight, so they don’t just dig at the bottom. If you need to put lumber in front of the tires to pop out of a rut, no problem with chains. Really hard to do without. But the tractor needs the HP and a darned low gear to lift itself out of a hole.
