My only addition to this is... Ford Website for my truck says my GCWR is 15,000... but because I have 18" tires.. I have to subtract 500lbs.. so my adjusted GCWR is 14,500.. So I would assume that number transfers directly across to the loss of power because of the bigger tires.. ..and when I lifted my 2000' Expedition, I put 7" Fabtech, and went from 29" to 34.7 (315/75R16 Mud Terrains) and MAN.. that was a huge hit on power and MPG... ( Had to get a tired reworked once.. took them off and put the stocks back on ... with the lift still on) and it went back to almost exactly what I got before.

So, long story short, you would be amazed the power & mpg loss from bigger tires alone.


<BTW - My truck is delivered!!! Just have to wait to get back stateside to pick her up & install all the mods sitting in my basement that the wife has been receiving from UPS / FED-Ex> lol