My Forgelines had these dimensions:skag said:
17x9.5 fronts with 42mm offset
17x11 rears with 46.8mm offset
I ran 275/40-17's on the fronts and 315/35-17's on the rears without problems. I did have to modify the rear fender lips and also beat in the frame rail inside the rear wheelwells slightly so the tire would stop rubbing it.
Now I run the tires on wider wheels from Complete Custom Wheel. They're:
17x10 fronts with 44.5mm offset
17x11.5 rears with 50.8mm offset.
No rubbing problems have surfaced with the wider wheels. Most of the extra width compared to the Forgelines is on the inside.
Andi