I'm guessing that even rolled +43 10" with a 275 will need some negative camber with a 1" drop. My +40 9.5" 255 gives me1-2mm of clearance on stock camber and a 1" drop. you're talking 20mm more of tire(roughly 8-10mm per side of the wheel) was more than that. You didn't mention having adj camber arms in the rear. I would love to see pics of this and what you had to do when you get them.

 

^ he's running 275/30/20.....what are you running? 255/35/20?

 

255 40 19, so my sidewall is a tad taller at 4.01 to his 3.24" and my overall dameter is .54 taller. But with the 255's that is inside what a 275 width would be by .39" per side so it wouldn't be a factor for rubbing.

My tire stats:

Section Width: 10.03 in 255 mm
Rim Diameter: 19 in 482.6 mm
Rim Width Range: 8.5 - 10 in
Overall Diameter: 27.03 in 686.56 mm
Sidewall Height: 4.01 in 101.85 mm
Radius: 13.51 in 343.15 mm
Circumference: 84.91 in 2156.7 mm
Revs per Mile: 769.5

His Tire Stats:

Section Width: 10.82 in 275 mm
Rim Diameter: 20 in 508 mm
Rim Width Range: 9.5 - 11 in
Overall Diameter: 26.49 in 672.84 mm
Sidewall Height: 3.24 in 82.296 mm
Radius: 13.24 in 336.29 mm
Circumference: 83.22 in 2113.7 mm
Revs per Mile: 785.2

 

it will fit fine after your fender is rolled...