I have an Ariens Zoom 34 zero turn mower. Last spring was quite wet here and it would get stuck when mowing. The stock rear rims and tires were very narrow at 18 x 6.5-8 and would just sink into the mud.
I wanted to mount much wider wheels and tires to get some floatation, but with the available tire sizes, diameter had to be increased as well. I decided on 20 X 11-10 tires.
The fenders were trimmed to allow clearance for the tires. Mud and lawn debris could be slung up into the now exposed wiring within the fender covers.
Fender liners were modeled up in Fusion 360 and printed in ABS at .2mm layer height and 80% infill. The liners were bolted in place after being cold vapor bathed in acetone.
The mower hasn't been stuck since the modification. One downside is the loss of side clearance due to the wider tires.