I mow with a JD4320, R4 tires, and a 6' bushhog. My newer 16 ac. field is always pretty wet in places. I'm tired of rutting it up and sometimes can't even get the job done. Would R3 turf tires work? My field's not perfect, but most of the rough stuff's out'a there. How do you guys handle wet fields? BTW, my GT225 JD lawn and garden tractor zips across the new field without breaking in anywhere. Of course, it's pretty light but does have turf tires.
I will guess that you don't really mean "Ruts", more like "prints" ?
It is MOSTLY about pressure, POINT PRESSURE that is.
If you have very wide turf tires with very little air between the rubber blocks the pressure where the rubber DOES contact the turf will be much lower than if you had R1s where there is a very big air gap between relatively small rubber bars.
At a guess an R1 may only have 20% of it's nominal contact area on the rubber that contacts the ground, vs maybe 80% in the case of turf tires.
Having a wider tire helps too, typically somewhere around 50% more width.
If these guesses are close you would have about 6 times the rubber contact area to spread the load over, resulting in 1/6 the pressure.
R4s ... ?? Somewhere in between, maybe they have 40% of their nominal contact area actually on the rubber - but are similarly about 50% wider than the R1s that would be standard on the same tractor.
Against this there is the very real possibility that turfs will a) Spin on wet grass b) plug up very quickly once they start to excavate dirt.
So while you have a somewhat better chance of "floating on it" you also have a better chance of getting stuck if you fail to float.
OTOH, you probably wouldn't be able to dig it down to axle depth in your attempts to get it out, so retrieval with whatever comes to pull it out should be easier (-:
