So, you’re keen to know the biggest tires you can fit on a Ford F150? Well, then this article is just for you! This article covers what sizes fit and what don’t with the stock F150 suspension running stock wheels. We also cover a complete list of the biggest and widest tire sizes you can fit on a 17”, 18 “, and 20” rim as well as what you need in terms of leveling kits, rim sizes, and the impact of removing the front crash bar.
So what are the biggest tires for a stock F150? The largest tires you can fit on a stock F150 without removing the crash bars are 33-34 inches without severe rubbing. Alternatively, you can fit 32-inch tires if your rims are 10” wide.
If you decide to fit the biggest tires you can squeeze inside the wheel arch, keep in mind you will experience a drop in MPG, and if MPG is a concern then I would recommend this article which discusses how big tires affect MPG in more detail. If you opt for a more aggressive AT or MT tire, you will experience increased road noise inside the cabin. In most cases, the more aggressive, the noisier.
Then there is the issue of the crash bars on all modern Fords. We’ll look into that in more detail and what it means if you do decide to remove them to fit oversized tires.
Let’s start with safety first!
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Ford F150 Crash Bars
Many F150 owners have confirmed that you can remove the front crash bars and swap them around with the passenger’s side crash bar. The reasoning behind this is the slight curvature on the crash bar will be just enough to allow the wheels to turn at full lock without touching.
So what’s the purpose of those crash bars anyway?
Well basically, Ford added those tubular bars in the front to increase the truck’s safety rating and earn them the top safety pick. This is, however, a bit of a contentious issue, since not all the models received them and buyers specifically opted to buy these trucks due to their high safety aspect. The problem is, not everyone was getting the same safety package, when in fact the protective steel bars were only installed on certain models and left out on others. Interesting!!!
These steel bars make quite an “impact” (no pun intended) in terms of your safety. Turns out the crew cabs who had them fitted aced the safety crash tests, while the ones exempt from them only received a dismal rating of “marginal” safety. OUCH!
So, armed with this information, make sure you understand what it implies in terms of your safety, in the event of a crash.
Okay, let’s get back to the biggest wheel sizes…
Have a look at this video and decide for yourself:
Right, moving along swiftly!
What are the Biggest Tires for a Stock F150
Back on topic, what are the biggest tires we can fit on a stock F150, without removing the crash bars and a small leveling kit?
Assuming everything else is stock, including rims and suspension, just a leveling kit.
Remember rim diameter doesn’t really matter since that only affects the sidewall profile. However, If you intend to go off-road at some point, the higher the sidewall, the better your traction once it’s deflated. A taller side wall allows you a larger, longer footprint, which helps a ton, especially when driving on sand dunes.
On the other hand, the bigger diameter rims like 20″ will allow you to fit a fancier rim, but limit you drastically off-road, since low-profile tires cannot be deflated that much off-road.
More important than the diameter, if we are looking purely from a fitment point of view, is the offset of the wheel and the backspacing. They are pretty much the same thing just the measurement taken from either the front or the back. The more negative the offset, the more the wheel will stick out. The more positive the offset, the closer it will sit to the inside of the wheel arch. A more negative offset rim might look tough, however, there is more risk of rubbing at the arches at full articulation.
Below is a list of tire sizes that fit 17, 18, and 20-inch rims.
Biggest Tire on Stock F150 17 Rim
So there you have it. If you want a complete list of all potential tire and wheel sizes ranging from wheel sizes 17-22 with tire width combinations then click here: Download the Biggest Wheel You Can Fit on a Stock F150 Fitment Guide FREE!
Biggest Tires on Stock F150 18 Inch Rims
Below is the list of tires you can fit mostly on a stock F150 with 18” rims:
If you want a complete list of all potential tire and wheel sizes ranging from wheel sizes 17-22 with tire width combinations then click here to Download:
If you are prepared to fit a leveling kit, you can squeeze a 35″x12.5″, 18”x9” AT tire on. It might require minor plastic trimming around the wheel well area, however, there is no rubbing or scrubbing with this combo. If you do not already own a heat gun to mold your wheel fender plastic for extra clearance then I recommend checking out this Top Selling Infrared Thermo gun on Amazon.
You Want to Go Bigger
If you want to go bigger i.e. 35×12.5 on 18×10 -44 wheels you will require a leveling kit as well as minor plastic trimming. There will be slight contact at full turn. if this is your intention going forward then I would recommend checking out this article to find out how to fit 35s on an F150 here.
Biggest Tires on Stock 2018 F150 20 Inch
Now, let’s look at the 20” tire and rim combos. Can this be done? Yes, we know it can be done and is rather popular, but let’s see what is possible with the stock F150 suspension
As you can see once you go 34” and bigger you’ll need a leveling or complete lift kit. 6” Kits are quite popular and allow you a wide range of options.
Bigger on 20s
If you want to go bigger on a 20” rim like say a 35”x11.5” on a 20×10 and -25 offset there will be some minor plastic modification/readjustment needed. There is no need to trim, however, you need to pull back and secure the inner plastic fender liner to the brace which is located directly behind the inner fender.
For this job, you will need a decent heat gun and Dremel Cutting tool. If you don’t already own one then I would recommend you check out this Top-Selling Infrared Thermo gun on Amazon with almost 17000 good ratings. Also, for trimming fender liners I recommend investing in this Dremel Variable Speed Cutting Tool (Amazon) It will give you better control than an aggressive grinder leaving your trimming looking a lot more professional and neat. You will also need a leveling kit and some height-adjustable struts set to 2.8”+
F150 2.5” Leveling Kit 35” Tires
The safe bet here would be a minimum 6” lift kit or leveling kit. You want to go 10 wide and -24 offset. That equates to 35×12.5. It’s quite an aggressive look and there definitely will be some trimming required to make them fit perfectly.
If you have a 4” lift then the better choice would be a 33×12.5” on a negative -24 offset.
Check out https://www.customwheeloffset.com/gallery for a comprehensive collection of rim, tire, and suspension setups with feedback from owners. You’ll see what the popular options are and what work is required in more detail. Big ups to these guys for creating this resource!
The Ford F150 is a fantastic truck to modify and allows you a whole range of options even in standard/stock form. Fortunately, the wheel arches on the F150 are still of the round design, which allows you to fit bigger tire combinations with more ease.
If you opt for anything bigger than a 33”, I would strongly suggest a full lift kit or a leveling kit. Not only will it eliminate most of the hassle of having to trim away plastic, but it also enhances the appearance of your truck.