Recently, we added a Rough Country leveling kit to our long-term 2022 Toyota Tundra Limited review vehicle. This one modification stirred up a lot of comments about adding larger tires to fill the fender gap better. This lead us to wonder: What is the largest tire size for 2022 Toyota Tundra?
Before we dive deep into different stock tires sizes with no lift and those you can add with a lift, there is a lot to unpack here. Not only could you be simply looking for the largest tire size for the 2022 Toyota Tundra, but you could also be opening up a Pandora’s box about what other modifications you have to make. Plus, there’s the issue of speedometer calibration for the larger wheel.
We will get into all of this information as it applies to the 2022 Toyota Tundra.
Let’s kick off this discussion with a stock 2022 Toyota Tundra. The owner’s manual offers four different 18-inch tire and two 20-inch tire options (page 551-552), and you can find this information on the door jamb on the driver’s side.
The tires are as follows:
Commonly people talk about tires in diameter inches with sizes like 32s, 33s, 35s and 37s. So, how do we translate the weird alphanumerical information from the owner’s manual into inches?
First we have to break down what each part of the number means.
For example, if we look at the first measurement 245/75R18:
To convert these hieroglyphics to a diameter in inches, you first have to take 75% of 245, convert it to inches (there are 25.4 millimeters to an inch, so that means dividing by 25.4). You have to multiply that number by 2 sidewalls. After that, you add in the rim size, and bam! Tire size in inches.
So, looking at that first line again, the math is as follows: (245 x .75 / 25.4 x 2) + 18 = 32.46, which translates into a 32-inch tire.
If you don’t want to do the math, check out this online calculator.
Using this same formula on the tire sizes above, we find the 265/70R18 is 32.6 inches, the 285/65R18 is 32.6 inches and the 265/60R20 is 32.5 inches.
In all cases, the stock tire recommendation is for a 33-inch tire.
It is also worth noting some tire manufacturers list their tires with inches first like a 33×12.50R15, which is a 33-inch diameter tire. So, it’s basically inches versus the metric system.
What if you want to go larger on the 2022 Tundra? You can, you just have to consider what steps you’ll need to take and how many modifications you want to do so you don’t get tire rub.
Basically, you are going to have to create room for the larger tire to fit, and this is usually a problem for the front of the truck. All trucks come with a built-in rake from factory which helps with aerodynamics and raises the bed higher to reduce the chances of sag on the rear end when you add a heavy load. Sag isn’t a big problem typically if you haul short distances, but it certainly doesn’t look good and excessive sag could lead to mechanical issues with the truck long-term.
For our truck, we went with a Rough Country leveling kit for no specific reason other than it was one of the only upgrades Rough Country had ready for the 2022 Tundra when we stopped by its headquarters. This leveling kit created more space in the front wheel wheels by raising the front end. The truck can now fit a larger tire much easier without worrying about rubbing against the fenders or control arms. We think we could go with 34-inch tires pretty easily with this setup and possibly a 35s depending on sidewall height of the tire.
Another option if you want 35s is to get a dealer-installed TRD lift kit, which Toyota showcased at SEMA. This lift kit allows for 35-inch tires, and you can see they are 35×12.5R20 if you zoom in close enough.
Sure 35-inch tires are great, but what about going really big? Say you want to go with the popular 37-inch tires or even larger with 40-inch tires? Well, then you are going to need to some more work.
First, you’ll need to do a lift kit, and then you’ll need to do some trimming like this option from Westcott Designs. In this YouTube video, you can see the larger wheels and hear how much trimming they had to do to the fenders and the front air dam.
Because we were curious, we asked if they had to remove the front crash bracket that is welded to the frame inside the wheel well. They said they did not.
This bracket is designed to stop the tire from entering the floor pan and injuring the driver or passenger in frontal collision with an object (think: hitting light pole, tree or crashing into the rear corner of a vehicle). This test is called the driver-side small overlap frontal crash test, which the Insurance Institute for Highway Safety started using in 2012. They added the sister test, the passenger-side small overlap test in 2017.
But back to the bracket. This bracket sticks out and intrudes into the wheel well behind the inside part of the tire. Turning left or right, the tire would hit this bracket unless the tire’s width was really thin or the wheel was offset and/or had some backspacing to move the tire more outward.
Westcott Designs said in their description, they used a true 37-inch tire, 18×8.5 with a plus 18mm offset. This positive offset means they were able to move the tire out from the truck, it extends outside the truck’s body and that helps them avoid the bracket.
Here is a good primer from RealTruck on what a positive offset does for your truck.
Finally, once you’ve got bigger tires installed, you have to think about how accurate the speedometer is now.
For example, using the Crawlpedia’s calculator, we can put in some different tire diameters to see how the speedometer is affected. We typed in a 35-inch tire, with 32-inch OEM diameter and 65 MPH. The result is an actual speed of 71.09 mph, so we are off by about 6 mph.
Besides knowing how fast you are going, another important note: Accurate speedometer readings are required by law, and your transmission may not shift correctly if the speed isn’t accurate.
In order to adjust this, we reached out to Toyota to ask how the 2022 Tundra could be adjusted by the owner to reflect the larger tire size. The answer is you can’t. The digital speedometer is part of the computer that houses the odometer. So, they don’t want you messing with this computer since that means you could also mess with the odometer and potentially, illegally, roll back the mileage.
The aftermarket does have some solutions like the HyperTech Speedometer Calibrator, which has had a device that plugs into the truck to adjust the speedometer for past models. As of publishing this post, they don’t have a current product for the 2022 model. However, since they’ve offered one in year’s past, it’s likely just a matter of time before they have one available for the new Tundra.
Larger tires always look great on trucks, yet it isn’t as simple as buying new ones and bolting them on. You’ll need to consider how big you want to go, other modifications you’ll need and how to get the speedometer dialed in. Oh and yes, you will be stopping at the gas station more often. That’s just the way physics works.
Wouldn’t a negative offset be required to move the tire away from the truck body?
“Westcott Designs said in their description, they used a true 37-inch tire, 18×8.5 with a plus 18mm offset.”