1. With 37-inch tires on the truck, it was decided to run all the tests based on factory wheels and tires to more closely relate to the majority of end users. Just for kicks, we ran the 37-inch tires on the dyno before the factory tire baseline to see what we were losing from tire diameter and wheel/tire package weight. Astonishingly, there was a peak-to-peak difference of 44 hp. The numbers came out to 249 hp with the 37-inch rubber and 293 hp on the factory wheels and tires.