I posted this over on hptuners forum with no response hopefully someone here has a answer-

I havent messed with one of these yet, but theres a couple i need to do tire size changes on to correct the speedometer. I've only found a couple thread pertaining to anything im dealing with and one guy had a issue with the abs/tcs lights going off when he changed the speedo in the tire size section on HPtuners. Is it just like all the older trucks where you simply change the tire height and gear ratio or is there more to the logic of these trucks?
Any help is appreciated! Thanks