Ok on my 2004 4X4 w/ a front leveling kit I had 305/65R18 BFG All-Terrains on stock Lariat wheels (18x7.5 w/ 6"BS). On my cousins new 2007 Lariat with the same leveling kit we just put 315/70R17 BFG All-Terrains w/ stock Ford Expedition (17x8 w/6.25" BS). The front of my tires barely rubbed the frame at full steering wheel crank and his are about 1" away from the same spot where my rubbed.

Now my tires were 305mm wide vs. his 315mm wide and he has an additional 0.25" of backspace. Both of those things should put his tires closer to the frame, so I can't figure out why they don't rub like mine did.

I'm wondering if the steering rack & pinion changed between 2004 and 2007... maybe the older trucks had a slightly larger turning radius. I wish I still had that 2004 just to try his tires and see if they would rub the frame.

 

There must be something different with the steering rack in the 2007. I just installed my ProComp lift today and when I got all done I had an extra bag with a separate instruction page in it. When I opened it up it was different spacers for the steering rack and the instruction page said it was for 2007 only.

2004-2006 use a 1" spacer on top of the steering rack, but for the 2007 you only use a 1/2" spacer on the bottom and a 1/2" on the top.