2011FX4boost

34.07" from what I found using a tire size calculator. That's the size I am going with.

kcb142

275-65-20 duratracs

2010stx4by4

Those would be 34.1"

Someone beat me too it.
I look on tire rack and find the size then look in specs.

klumb15

A 275/65/20 would put him in the same dilemma as they are all load E in that size as well. 275/60/20's are p rated but regardless, the OP doesn't want 20's.

Hopefully some more air in them will help a little. Has the truck been re calibrated for the taller tires? Or have you taken into account the tire diameter difference when hand calculating your gas mileage? If all else fails, the truck looks great! Get a leveling kit and enjoy the look.

HoustonRider

Some people say unsprung weight isn't an issue. It used to be unsprung weight was like 9lbs for every 1lb u actually added.

If you add 10lbs to each tire, or 40lbs total that's equal to 360/lbs in the bed of ur truck ( in theory). Larger diameter slows rotation, so less rotations per mile. That's good. But nobody has a taller tire that weighs less than the small ones. The problem with larger tires is you always get more rubber, Kevlar, steel, etc and that will add 20lbs per tire. Or 80lbs, or 720lbs

Rutko

thanks, just the 0 offset, no wheel spacers

http://gti-vr6.net/library/engine/Sc...ldiameters.htm

blyons808

No it hasn't been recalibrated. The dealer can only recalibrate it to raptor size (35") and I can't drop a few hundred dollars on a tuner. I haven't hand calculated, but I know my truck and I can tell that there is a major drop. As for the leveling kit, I don't think I'll be adding one. The rake looks really bad in that one pic because its on a slope, but its not actually that bad on flat ground. Plus, I can't find anyone who will do the install for under $400, I just don't think it's worth that much lol