Yeah, I'll agree. 285 is a wide tire for a medium final drive gear. Maybe 265 would help. Gotta take into account unsprung weight. I was getting 12.5-13 after getting the speedo right on 285/75/17's, 10ply, aluminum wheels, and 4.10s. After tuning and letting it actually make power it gets like 8-10.5. But I'm fine with that, it drives so much better now.