My buddy put the big revo's on his 2001 and a full size spare as well..
He's lost 3 mpg but likes the look.
I steered clear and still get 19-20 mpg highway.
Sounds dumb but these days........Gas is expensive and we've only got 18.5 gallon tanks.
The change in drivetrain numbers causes his truck to go in to overdrive when he hits any incline on the highway.
Caused by the taller tires I'm sure.
My old Suburban with 33's would slug up long grades due to the taller tires. Kenny S>