375's or 35's?
 

I'm going to be getting my first f150 this weekend (06 King Ranch) and my plan is to put a 6 inch lift on it. I'd like 20x10 or 20x12 rims and I'm curious if the 37's will fit without any issues, or if I need the 35's for this set up. I don't plan on taking it off roading all that often, maybe just a few times a year with my friends that have trucks. I'd love to hear all feedback and ideas. I'm pretty new to the truck scene.

Thanks Guys

Yes 37's will rub a lot, I think. Also, 10" is plenty of rim width. Even with 35's you're going to take a pretty big hit, power wise. The best case is if the truck currently has 3.73 gears, that'll maximize power to the wheels. I would start budgeting for a gear swap. After going to 35's on my '05, I re-geared to 4.56 and it's a whole new truck.

Even if you get enough lift to clear 'em, 37s are WAY too much tire for that truck. You'll tax the piss outta your diff(s), axles, trans, brakes.. 1/2 tons just don't have the components to handle that big of a tire. Hell, even 3/4 tons should be re-geared for 37s-at the very least.
You'll even wanna re-gear with 35's

37s will fit with a 6” lift depending on the actual tire size ( some 37” tires are really only 36.5 inches) and lift kit brand. I fit 37” nitro terra grappler g2s on my 2004 with a 6” rough country lift. All I had to trim was the plastic piece below the front bumper. It ran fine with no rubbing at all but I ended up doing a 3” body lift and 4.56 gears.

35s