The owner's manual for my 4010 says 22x9.00-12 4PR front and 29x12.50-15 4PR rear for R3 turfs. The R1s are 6-12 4PR front and 8-16 6PR rear. So, looks like the R1s are put on different wheel diameters in the rear. You'll have to check with some tire outfits to find out what tires would be the same diameter on the bigger rims.
Might be easier to get new tires and rims. This is what I did for my Gravely. Had 4 sets of turfs and 4 sets of ags all on rims for my walk-behind (single axle) Gravely. Of course, they'll be a bit more for your JD but not much more. Be a lot easier to change out whole tires on rims rather than have to remove the tires.
I went with the turfs on my 4010 based on my combined experience with turfs and ags and ags with chains on the Gravely. Both ags and chains have a bit more grip on slippery surfaces (snow and mud) before break but dig like crazy and mess up the ground when they break loose. The turfs have more grip before final slip on most surfaces (not mud and wet snow), including dry snow than ags or chains.
I use the ags on the Gravely in winter and mud. Otherwise, the turfs work better.
Ralph
