The Ford F250 must be one of the coolest trucks ever built by Ford. It, therefore, comes as no surprise that it’s so popular and that so many owners fit bigger tires to these vehicles to enhance their appearance even more. Being such a big truck, 37” tires are becoming increasingly popular since they fill those arches so well and really enhance the aesthetics even more. So what are your wheel options when fitting 37s to your F250?
You can fit 37×12.5 on 20” wheels to a leveled Ford F250 with a 2.5 spacer kit. It is recommended to fit 2” caster shims to restore your caster angle back to the factory. With a 0 offset rim, the tires will stick out past the fenders approximately 1 inch.
These offsets with zero rub are very popular with these 37×12.5s. There might be some minor plastic trim required, depending on which offset rim you opt for and how aggressive the tire tread pattern is.
Let’s now look at your fitment options in a bit more detail.
Will 37s fit on a leveled F250 – ALL YOU NEED TO KNOW
After spending many hours researching this topic to find out exactly which offset really works best with and without plastic trimming required, I found it so interesting how much these trucks vary. Some guys literally managed to fit a 2.5 ” ReadyLift kit with 37s on a stock truck and it sits as if it is running on 35s. No Scrub.
With that being said, another important question to ask is, does a 20×9 vs 20×10 wheel make a difference, or is it strictly the width of the tire that makes the issue?
Let’s see which options are most popular
- 2.5″ Readylift leveling kit
- Track bar relocation bracket
- Rims are Fuel in 20 X 9
- +20 offset rims
- Toyo 37 X 12.5 X 20 tires
- 2.5 Inch Readylift kit.
- Rims are 20×10
- -18 Offset
- Tires are 37×12.5×20.
- Minor scrub.
If you opt for a 20×10 rim then go for a more negative offset rim to keep scrub at a minimum. Of course, the opposite applies as well.
Will 37s fit on a leveled F250 – Leveling Kit
When fitting a leveling kit to the front, some owners have reported the truck stance to be a little nose high. This can happen depending on the truck’s year model, so keep that in mind before going too high on the front. Some F250 owners actually prefer it a bit nose high, however. I’m not exactly sure why that stance is appealing.
When it comes to the rear, you want to fir a rear block to lift or level the rear out to improve the stance of the truck a bit. When fitting a rear block, these vary in height according to vehicle year model.
For example, the 2020 F250 uses a shorter rear block and many owners have success with a 2″ rear block compared to earlier models between the years 2017-19 that require a 3.25″ or even a 4”. That difference in block heights has no negative side effect when running 37s.
Fitting 37s on Stock Rims
If you want to fit 37s while keeping the stock rims/wheel then you will be limited with tire options. Most owners reported that the only tire that fits nicely without any scrubbing is the Nitto Trail Grappler MT 37/ 11.5 r20. In this instance, the 11.5-inch slimmer width prevents any rubbing. Unfortunately, the tire options in this configuration are very limited.
This is one of the few options available if you are not prepared to move away from the stock wheels and want to prevent any rubbing. With even the stock wheels, in order to fit 37’s will require a minimum 2-inch leveling kit.
If you are running 18” stock rims your rear clearance and offset is limited so to rectify that a 1/4″ wheel spacer usually does the trick to push the wheels out a bit with 18X8 factory wheels.
Will you need Caster Shims when lifting your F250?
When lifting most trucks, especially those with IFS setups, you are altering the geometry of the suspension angles. Simply fitting a leveling kit affects the caster and front-end stability. It is therefore highly recommended to install 2° caster shims to restore the factory angles and prevent the so-called “death wobble” effect. It’s a worthwhile layout and inexpensive with many aftermarket options readily available.
The 2° shim specified with our 2.5″ lift systems not only restores the caster but increases it by 1° from the stock spec to ensure proper tracking with larger tires.
Which wheel offset works?
20×10 with a -18 offset combined with 37×12.50 AT tires requires a minimal amount of plastic trimming. The upside to this configuration is in most cases there shouldn’t be any rub on the UCA arms at full lock.
If you opt for wheels with less offset, in most cases there’s no need to trim anything for the 37s to fit. If you opt for anything more than -18 like say a -24 offset wheel, be prepared to do some minor trimming.
Will You Need to Trim Anything?
Cutting up your truck is never fun no matter how minimum they are. In some cases, however, again, depending on offset, tire choice, etc., you will be required to trim the area where your front mud flaps mount. Be prepared to take about an inch off.
There will be a slight rub occasionally when turning at full lock while backing uphill. To prevent this, as mentioned above, you need the correct offset and aftermarket radius arms to get no rub.
Will you lose power after fitting 37s
In my research, I’ve seen quite a few F250 owners complain that 37s are noticeably sluggish over a 35. Owners who tow and haul heavy loads report the power loss is minimal and nothing noticeable between before and after 37s.
Other owners, on the other hand, report that they did not feel the truck lost any power or acceleration when tested on the dyno.
Your heavy 37s being below the suspension fall part of the truck,s unladen weight, which means you should be prepared to lose 1-2 MPG in fuel economy. There’s no way of escaping that.
WATCH – FITTING 37’s TO A LEVELED 2020 F250
Biggest Tires on an F250 – No Lift
Before you run off and slap on the biggest tires on your truck, you need to consider what your intended purpose is for the upgrade. Are you going off-road? Are you simply doing an aesthetic (looks) upgrade? Is the truck used for hauling, commuting, or towing? All these factors will play a part when considering a big tire upgrade. Your motive for the upgrade should be to determine what the biggest tire size you SHOULD fit for your application, rather than what the biggest size you can get away with. Bigger is not always better in all scenarios.
Your tire and wheel selection should be in-line with your application. A big tire upgrade with a smaller rim and taller sidewalls for off-road purposes will be very different from that of a bigger diameter rim upgrade with lower-profile tires, which is purely for aesthetics.
As mentioned from the outset the largest you can fit without and scrubbing, or cutting of wheel arch plastic is the 34” on a 16” inch rim. (eg. 315/75/16) Most popular combinations of 34” can work.
If you are prepared to remove the mud flaps, you can go slightly wider with a 295 tire on an 18” profile.
Once you install a small 2” lift your tire and rim options immediately widen, so let’s see what your options are.
Biggest Tires on Stock 2017 F250 4×4
The biggest tire you can fit on a 2019 F250 with no suspension upgrade or aftermarket rims are: 275/65/20 or 295 on an 18”. If you are prepared to fit a 2” lift you can comfortably get away with a 37”x12.5” R20 wheel.
F250 User Experiences/Feedback
Let’s look at a few real-world examples of F250 owners that have fitted 37s and their experience.