Any commercial-type vehicle including pickups will have variable alignment specifications depending on ride height, sometimes pretty radically different ones. At a bare minimum, most truck alignment specs include a "frame angle" check. I'm always amazed at how much misinformation there is out there about wheel alignment, and how dangerous some of the supposedly "no problem" modifications can be. I've worked on suspension systems and taught wheel alignment for many years, and I'm pretty convinced that any change in ride height over about 2" will induce changes in steering geometry that cannot be corrected by wheel alignment adjustments. On the round track race cars I've built, we always had to relocate control arm pivot points to get the correct suspension geometry when altering ride height, and all we had to worry about was "go fast- - - - -turn left!" Making a vehicle handle under street driving conditions requires an understanding of 3-axis trigonometry that very few hobbyists have. Most professional mechanics don't get that deep into alignment theory!
Jerry
