Well I bit the bullet yesterday and bought a new set of tires. I didn't end up with the Nitto Trail Grappler but instead I bought the tried and true GoodYear Wrangler in a 275 70 r18 which gives me a true 33 inch diameter as measured on the truck. They run quieter and smoother and were about 30-40 bucks cheaper per tire. I'm ready to get out and put them through some testing this weekend.