Well I solved my problem with my tires. I'll give a little history of my tractor first, prior to the answer. The L185 came in three different versions, the L185TP (mine) was the turf model, the L185FP was the farm version, and the L185DT 4wd. The only difference (to my knowledge) between TP and the FP were the ag tires.
From online research, I could not locate a 13.6-16 ag tire. I did however, find a 12.4-16. I discovered that the 12.4-16 is generally installed on an 11 inch wide rim, mine (as stated above) is a 12 inch. Could this work? I checked with my local Kubota dealer as to the cost of the ag rims to fit my tractor. They were over $600 a piece. No thanks. The dealer, only looked at me with a blank confused stare when I asked if the 12.4 tire would work.
I then met with a local tire shop, who confirmed that the 12.4 would fit. The only down side is sitting about 2 inches lower. Due mostly to the tire spreading out the extra inch for the rim. The total cost of the 2 Firestone R1's with install & disposal was $678.38.
