Whats is the biggest tire I can run with just a 2.5 level kit, and 18x9 wheels, on a 2006 F250 super duty without rubbing ? Pictures would be GREAT. Thanks to all of you that have helped already.

 

I'll try to help you out I've run several sets of tires, so here's some of them:

33s on 18s, 2" lift, no rubbing, also fit without a lift (factory 6000# spings)

(Yes, that's my lazyboy in the bed. College was awesome)

35s on 17x9s, 2" lift, rubbed at full lock


34s on 18s, 2" lift, also fit with no lift


34s on 20s, no lift, factory 5200" springs, for reference on filling the wheel well


The 35s rubbed at full lock, because the backspacing on the wheel pushed them too far out and the outer corner of the tire rubbed. That's the biggest problem with aftermarket wheels, they're wider and the backspacing is almost always deeper than factory wheels, so the centerline of the tire is going to end up pushed further out than factory wheels. 34s on factory wheels won't rub even without a lift, but 35s on aftermarket wheels will rub with 2" of lift. 1/2" more sidewall, 2" lift, more rubbing, that's some crazy math, and that's why backspacing is so important.

Figure out the backspacing on your wheels before you buy anything. A 34" or smaller tire shouldn't rub under a 2.5" lift even with wheels that stick out quite a bit more than factory. If your new wheels have a shallow backspacing, you should clear 35"s fine. If you're looking to make the jump to 37s, a 4-6" kit with either radius arm relocation brackets or a 4-link setup is where you're going to have to go, and that's a whole new ballgame than just a leveling kit.

And in the future, if you seach the forum, you'll find dozens of tire size threads that answer basically every question you could think of. Searching is a lot faster than waiting for someone to respond, too.


EDIT: Quick side note, my truck has 6000# factory springs. The 250 Lariat with the 20s has 5200# springs. With the diesel engine, going from 6000# to progressive aftermarket springs will probably mean you only get 2" or less of actual lift, that's why I used blocks on my truck. With a lighter spring, say 5200#, and/or a gas engine, you'll probably see a total 2.5" lift with new springs.

 

I came from a car world (03 cobra) and liked the rims it had. I'm looking at moto metals 950 18x9 with a (305/60/18 -32.6 outside dia.) or a toyo 33X12.50R18LT- 33 outside dia. But not to sure on fitting width I think backspace on wheel is -12mm Offset, and 4.5" Backspace does this sound write. I find pictures of trucks I like but cant find out what size tires/wheels they have.

 

Width of the tire will count too, just like backspacing. The width of the tire moves the "rubbing" edges in or out. I'm likely to get a tire that fits a 7.5" or 8" wheel and try to keep things narrower, but taller (like a 255/80/17E, a tall 33x10x17)

 

That's exactly what my 17's spec'd out to. 35x12.50s rubbed both ways on flat ground, turning up my driveway wasn't a pleasant experience. 33s would have probably worked fine.

I did skip that part I guess, I just assume that people are smart enough to put tires on the correct rim width. 9" wide rim shouldn't take anything over 13" or 325mm.

 

Gallery for Moto Metal MO951 Wheels down to blue and tan truck what size tire is this

 

Oh I didn't mean to imply you missed it, or that people wouldn't know what tires to put on what wheels (although that does happen quite a bit I guess). I was just pointing out that backspacing moves the tire in or out, and the width of the tire also means it's in or out further (i.e., a 33x10x17 and a 33x12.5x17 tire might both fit on an 8" wheel but the 33x12.5x17 might rub and the 33x10x17 might not because the tire isn't as wide...works relative to height too). With height, a 35x10.5x17 might not rub, but a 33x12.5x17 might rub if they are both mounted on the same wheel.

I was just trying to point out that where the tire rubs, fender, bumper, etc is as much an issue with height as width of tire as width of wheel as backspacing.

When you start turning the tires all of the measurements change relative to what the tire might rub against. And, the tire, wheel, backspacing all impact that.

 

Good point Ace