Just wanted to dredge this up- I LOVE THESE TIRES! They are smooth and soak up the wash board and bumps like it's not even there. I took it out into the field coyote hunting and they scratched and clawed through 12"+ snow (24"+ in a few spots) without hesitation. These buggers are heavy (like was mentioned earlier) and you sure notice it. As for mileage hit- yeah, pretty sure I took a hit but I can't say how much since I think my original tire calibration was off from factory? It was 33.05. On a stretch that I know always uses 1/8th tank no matter what I still used that 1/8th tank. We'll see. My average at highway speed (110km/h) is now 16-18 l/100km and before was 14-16 l/100k real time. That said, it's now -20° so I suspect that doesn't help, and they haven't had many miles to "bake". For some reason my Eco kicks in a lot more often now, can't really explain why. After calibrating to 34.5" the speedo exactly matches three GPS readings.
Thanks everyone for the advice!