They don't know whether they've got an F-150, C10, or K1500. They don't know if the pickup is a compact or full-size. They don't know the size of the engine or the gear ratios. Many times, they don't even know what year the truck is. If you don't know your truck, there's no way you can order accessories intelligently.
Most guys have no idea what it is.
If you go to a larger tire without changing the differential gears, you're going to have a power loss. You hit a deep trough of mud-well, you're just going to sit there because the truck is underpowered. But there's something else as well. With some guys, after you explain that all this gear work can cost a couple of thousand dollars, they tell me, 'Oh, I don't want to do that. A Different Beast Diehl pauses, swivels in his chair for moment, and then gets back to business.