I just lifted my truck and put Pro Comp 35x12.5x17 tires on it. I bought a SCT SF3 from troyer, i am waiting for my custom tunes but i figured in the mean time i would use strategy tune to correct the wheel difference. When i got the truck back the spedo was only 1mph slow with out the tune. I used a few tire calculators and this fourm and determined that my tire revs should be around 575. When i tuned my truck to 575 it drove better but the spedo was 6mph fast, i tried to adjust it to get it right and went all the way up to 625 and it is still 4-5 mph fast. Does anyone know why this is, am i doin something wrong, is there something wrong with the truck / tunner.