rancar and Henro,
I agree with you both. I was told not to mismatch the tires with 4 wheel drive. My experience is R4's both front and back and love them. Because of the size of my tractor and my new lawn I do have to watch it some when mowing. As far as turf on the front, my dealer took me on two tractors on a wet day, both TC21D's. One had turf, one had R4's. He drove the tractor straight a bit and then made a real sharp turn on each tractor. To my amazement the R4's did less damage to the grass. So I went out and did some research on tires and sure wish I could find that page again but that is exactly what my dealer told me. R4' will do less damage on grass in the turning modes and the turning modes only. Turf was still better on grass on the normal straight runs. I also like my R4's for plowing snow and using the FEL. If my work was mostly finish mowing, then I would go turf.
Murph