Valaar91

Hi, just bought a 05 F-150 Lariat Supercrew 5.4Triton RWD. Since I got it I put a Rough Country 2.5inch leveling kit on it, and I'm looking to put on bigger sized tires, so my truck has a more aggressive look. So my question is, what's the biggest size tire could I put on my new truck without killing my transmission? The stock recommended size is 265/60r18, and has 3.55LS gears.

PerryB

275/70-18 would be a good size.

johndog82

iTrader: (3)

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johndog82

iTrader: (3)

I have 275/55R20 (32") and I personally would never go bigger than this on my 3.55 and even this is pushing it imho.

Manuellabour247

56". Go big or go home.



Just kidding. I'm pretty sure the biggest tire you'd want to fit in there with the mods you mentioned would be a 35" tire. Any bigger and you'd have to have more lift or the correct rim with the right offset. There's several threads about tire fitment. Some are stickies at the top of the page. Might have to look at a few different generations to find the correct one.

SnowDawg

I don't have the 5.4L, but 35's where very sluggish on 3.55's. I've done 305/55/20 and 285/65/20's and both downshifted like crazy too. I'd stay smaller after those experiences

boom50cal

run a 305/50/20 here. Would like a little more gear every once and while, but truck hasn't been stressed too bad with them. Only time I didn't like them was climbing hills with our 57 Fairlane on our tandem axle bumper pull. Stayed downshifted in 2nd the entire time at 55 or so.

DUGIE FRESH

Got 315/75/16R on this 2WD 4.6L. Running 3.55s. Was sluggish until i added superchips programmer, Flowmaster 40 with 2.5 exhaust, aluminum driveline and cold air intake. Its nice and quick now, feels like it lost a ton of weight. 4.10s are my next purchase though, but for now it gets up and goes.