“9.2.12 Crandon Off-Road – BF Goodrich Off Road Tires” byroyal_broil is licensed under CC BY-SA 2.0
It’s an age-old question that haunts every off-roading group on the internet: What is the right tire size for overlanding?
As overlanders and four-wheel drivers, we love our trucks, and for many the bigger it is the better. Bigger tires are a great way to make your truck look tougher but without the right modifications to back those tires up, deep down, your truck might be weaker. Choosing what size tire to use is based on three factors: your vehicle, your budget, and the terrain you will be crossing.
Before we dive into what the right tire size is for you, a good understanding of how to read tire sizes is needed.
An example of a tire size code is 285/75R16. At first glance this might seem confusing; however, when you break it down it is really simple…
The 285 is the width of the tire and the 75 means that the tire’s sidewall is equal to 75% of its width. Finally, the R16 is the size of the rim; in this case, it is 16 inches.
A 275/65R16 is a 31-inch tire, a 285/75R16 is a 33, a 315/75R16 is a 35 and a 385/70R16 is a 37. For overlanding, anything bigger than a 37 will be too much of a compromise when it comes to on-road travel (more on that later).
Let’s have a look at the benefits of bigger tires.
On a Solid Axle Vehicle, It is the Only Way to Lift Your Diffs
When installing a lift kit on a solid axle truck, everything is lifted except your diffs. This could be an issue in deep ruts, mud, or rocky terrain because you run the risk of bottoming out. This means that the right tire size is to go big. Keep in mind that a two-inch increase in tire size will only lift your diffs by one inch. On an independent suspension vehicle, this is not an issue.
A larger footprint equals more traction. This is part of the reason why we air down our tires. On snow and sand, a larger footprint can also help glide over the terrain because the weight is distributed through a larger surface area, preventing the truck from sinking. If you want to see this in action search for videos of Arctic Trucks! You will be amazed.
The Right Tire Size: Big Tires Roll Over Holes, Ruts, and Rocks Easier
A taller tire can help overcome obstacles more easily. A hole that would swallow a 31-inch tire will be no issue for a 35. To put it simply, larger tires will drive over ruts and holes because they won’t fit in them!
Now for the negatives. They are plenty!
The Larger the Tire, the Heavier It is Going to Be
It might be the right tire size for your needs, but a bigger tire is a heavier tire, and it will put more strain on almost every single part of your drivetrain from the engine to the axles. Because of that, items may break more easily or wear prematurely.
Getting the Right Tire Size: They Might Not Fit
Depending on your vehicle, there might not be much space for bigger tires.
For example, my truck is a 90 series Landcruiser Prado and on stock suspension, I can only go from 31s to 32s. Keep in mind that the 32s on standard rims rub on full lock. With a 2-inch lift kit, I can fit some 33s in there but that’s about it.
On something like a Jeep Gladiator or an 80 series Land Cruiser, you can fit 35s with just a 2-inch lift relatively easily. Our very own Alex went for the Nitto Trail Grapplers in 35s on his 2020 Jeep Gladiator with no issues. This goes to show that your truck will play a huge role in the right tire size for your needs.
Fender Flares Might Be Needed to Stay Legal
If the right tire size is much bigger than the factory size, it will probably stick out of your fenders which might be illegal.
Additionally, a negative offset rim or a small spacer might be needed to keep the tire away from suspension components. This will push the tire out even further. These issues can be easily addressed with some fender flares, but keep in mind that you might need to drill some holes into your vehicle to install them.
Your Truck Will Burn More Fuel
Imagine someone makes you put on some heavy shoes and asks you to walk around with them all day. You will need far more energy to move those suckers around! The same applies to your truck.
With the larger surface area comes more friction and weight; therefore, more energy will be needed to move those tires. Additionally, a larger tire harms aerodynamics, and that’s especially true if you add fender flares. This can be something you might want to consider if you are planning on traveling to very remote areas where fuel isn’t available.
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Carrying a Spare Tire Might Become an Issue
On vehicles with a rear-wheel holder, the right tire size may now be too big to fit in the factory trunk cut out. Meaning, you may need to buy a rear bar with swivel arms to carry it. Although, this probably won’t be a problem if the increase in tire size is small.
You Might Need to Regear Your Vehicle for the Right Tire Size
This starts to become a problem with tires larger than 35s. Because of the large diameter of the tire, first gear low range may now be too fast for your liking. The only option is to regear your truck to bring everything back to normal.
Now that you know the pros and cons of installing bigger tires it is time to decide the size you will be going for.
As mentioned above, the three most important factors in choosing tire sizes are the terrain you will be crossing, your budget, and your vehicle.
Choosing the Right Tire Size: Consider the Terrain
“Walking / Biking the world’s most dangerous road in Bolivia” byAlex E. Proimos is licensed under CC BY-NC 2.0
If most of your overlanding trips are on dirt roads and mildly challenging trails, a 33-inch tire will be more than enough. On more difficult trails with deep ruts, mud, snow, and rock gardens, a 35 will provide the added clearance and grip needed to tackle these obstacles.
That being said, I wouldn’t go much bigger than a 35 on an overlanding trip because of the compromises it comes with when covering long distances.
Choosing the Right Tires: Your Budget
As you will see further on in this article, the bigger the tire, the more money you will need to spend to make it work properly. Depending on the tire size increase, you will probably have to invest in a quality lift kit, rims, and other suspension components.
Choosing the Right Tire: What if Your Vehicle Has an IFS?
On most independent front suspension (IFS) rigs, installing tires bigger than 33 inches can be an issue. They usually have less space in the wheel arches and the suspension components aren’t as strong; meaning, they won’t be happy with the added weight.
Additionally, lifting an IFS more than 2 inches to accommodate larger tires starts to become expensive and impractical. A new set of control arms will generally be needed along with a diff drop to bring those CV axles back to normal angles.
When lifted excessively, IFS trucks lose most of their downward wheel travel and drivetrain components tend to be stressed excessively. However, they make for great overlanders because of the sure-footed handling and great ride quality.
Therefore, if you are planning on adding bigger tires to your IFS rig, I would suggest going up to 33 inches with a 2-inch lift. This way, you will add a lot of capability while also keeping everything in one piece.
Choosing the Right Tire: Solid Axles
“TJM North America Toyota Land Cruiser 80 Series ADV80 GCRad1”by GCRad1 is licensed under CC BY 2.0
If your vehicle happens to sit on solid axles, then you have far more options; and I am jealous!.
These types of trucks do not have the same issues as the IFS ones when it comes to lifting them. A solid axle vehicle will work perfectly with a 4-inch lift. Granted, some further modifications might be needed but they tend to work great after everything is sorted.
Because of the larger lift, there is far more space for bigger tires. Besides, due to their simplicity, solid axle trucks tend to be very strong, so large and heavy tires are welcome here.
Generally speaking, most solid axle trucks can be fitted with 35-inch tires without too much drama. Thus, the most important factor when choosing tire sizes for your solid axle vehicle is the terrain you will be crossing.
I hope this article has helped you understand the pros and cons of upgrading to bigger tires. If you have any questions, feel free to ask them below!