coollx I wondered the same thing R3 or R4.
The R3 tires I have seen on the new 2520 are a Carlile brand.
They sure did seem to have an agressive tread on them. I wanted to find a picture of them on the web, but didn't find any.
I also will use them in the snow, but primarily mowing in the summer.
Do you kow what model Carlile tire you have?
PS It seems to me the tread on these R3 turfs aren't like previous treads I have seen on turf tires.
Do the rest of you also clear snow in 4WD?