If there’s one thing that overlanders are obsessed with, it’s tires. Forums and Facebook groups are filled with questions about the best tires for overlanding. I get it. We all want our overland rig is equipped with tires that are best suited for the terrain you’ll be tackling. With that we’ve created a comprehensive guide to help you choose the right tires for your off-road vehicle.
There are four things you need to think about when choosing the right tires:
- What’s your primary terrain? Mud, sand, rocks or a mixture of terrain?
- Do you understand tire numbering systems?
- Is the tire is compatible with the make and model of your vehicle ?
- Will you need to make any adjustments so your vehicle will still run smoothly
If any of those questions made you pause for a second and thank about your vehicle don’t worry, we’ve got you covered. Continue reading because we’re covering off-road tires in detail below.
Table of Contents
- Factors to Consider Before Converting to Off-Road Tires
- How to Read Tire Measurements
- How to Calculate the Outer Diameter of Your Tire
- What Is the Speed Rating & Load Index Numbers of Your Tires?
- Wide vs. Narrow Off-Road Tires
- All-Terrain vs. Off-Road Tires vs. Winter Tires
- Consider the Rubber Compound
- Upgrading Your Rims/Wheels for Off-Roading
- Keep Your Off-Road Vehicle Street Legal
Factors to Consider Before Converting to Off-Road Tires
Changing from standard to off-road tires can cause a few changes to your vehicle. It may affect the vehicle’s performance in a way that you weren’t anticipating. So, before you decide on which tires you need, think about how they’re going to affect your rig.
The Size of The Tire
Most people think larger tire size means better off-road performance. In many ways, it’s true. But not all rigs are ready for large, beefy tires without a lift. Before you commit to lifting your overland rig, you should be aware of the effect that it’ll have on the mechanics of your vehicle:
- Change the geometry of the suspension system
- Put stress on other parts of the car
- Lower fuel efficiency
This isn’t meant to discourage you from lifting your rig. Lifting your vehicle to accommodate larger tires will turn your vehicle into an off-roaring machine. If you’re using your vehicle as an every day driver, then be aware that it will have an impact.
Big tires are heavy. Because of that you’ll need more force to get your vehicle moving. This will impact your gas mileage. For some this may be a deal breaker. There are way’s around it. You may need to upgrade the driveshaft or reduce your gear ratio to get more power to turn the massive wheels.
3.78 is a common gear ratio and it’s what I have on my Tacoma TRD Off-Road. You’ll see lot’s of posts around the web about people changing their gears to a 5.29 ratio. This will help, but it isn’t necessary. Plus, changing your gear ratio isn’t a DIY job. You’re going to need to have a good shop with a mechanic that knows what they’re doing.
You may also have to upgrade the axle, change to longer shocks, and extend the brake lines to accommodate a larger tire.
How to Read Tire Measurements
If you take a good look at your tires, you’ll probably notice a number that looks something like this: 285/70R17. It might look like a random assortment of numbers and letters, but they’re not random at all! That’s the tire’s size. It can tell you the height, width, and rim size:
- The “285” refers to the width of the tire. In this case the tire is 285 mm wide
- The “70” refers to the sidewall height percentage compared to the width. In this case the height is up 70% of the 285mm tire width
- The “17” refers to the diameter of the wheel in inches
Some tires come with imperial measurements that might look something like this: 33×12.5R17. This still shows off the height, width, and wheel size, except there aren’t any percentages (No math necessary!). The first number is the height of the tire in inches. The second after the “x” is the width of the tire in inches. And the final number after the “R” is the diameter of the wheel in inches. Simple as that.
How to Calculate the Outer Diameter of Your Tire
When you replace your factory-sized tires, you don’t have to worry whether they’ll fit. But if you decide to upgrade to a more rugged setup, you’ll have to determine if the bigger wheels can even fit in your wheel wells.
To do that, you’ll need to calculate the dimensions of the tire in inches. If you buy tires that use imperial measurements, that’s easy. Just read the numbers. If you choose tires with metric measurements, it takes a bit more math.
To calculate the outside diameter of a tire:
- Multiply the width X the sidewall percentage of the tire:
- Ex: 235 mm X 0.75= 176.25 mm of sidewall height
- Convert mm to inches by multiplying by 2 and then dividing by 25.4:
- Ex: 176.25 mm X 2= 352.5 mm/25.4
- The sidewall height of this tire: 13.88 inches
- Ex: 176.25 mm X 2= 352.5 mm/25.4
To find the total diameter of the wheel:
- Add the sidewall height and the diameter of the wheel from the standard measurement
- Ex: 13.88 inches +17 inches = 30.88 inches in total diameter
If you’re like me and think that’s way too much math, there are plenty of online tools to help out. Tire Size Calculator is a handy tool where you can just plug in the tire measurement and get the exact dimensions you’re looking for without breaking out the calculator.
What Is the Speed Rating & Load Index Numbers of Your Tires?
As you might have guessed, the speed rating and load index is how fast the tires are meant to spin and how much weight they’re designed to carry respectively. Whenever you’re choosing new tires, it’s important to look at these numbers to make sure the tires are suitable for the activities you’re going to be doing.
Next to the tire measurements, you’ll see another number and a letter. For example, it might look like 275/75R17 116L.
- The “116” represents the tire’s load rating
- The “L” represents the tire’s speed rating
Load Index Number
The load index number will help you calculate the total weight the tires on your vehicle will be capable of carrying when the tire is properly inflated. A higher load index number corresponds to higher load capacity.
The “116” load index value is a fairly high load index value. It corresponds to a load capacity of 2756 pounds. Placing 4 of these tires on your vehicle yields a total load capacity of 11,024 pounds.
This sounds a lot, but you do need to keep a couple things in mind:
- The vehicle’s gross vehicle weight (GVW) includes the weight of the vehicle itself, the weight of the passengers and gear, and the weight of any modifications you make.
- If you’re off-roading, you may not have all your tires fully-inflated to improve off-road performance, which will impact your load index.
Since the load index value represents the load capacity when the tire is fully inflated, you should seek out off-road tires that have a higher load index value than the factory-standard tires for your vehicle.
Tire Speed Rating
The tire speed rating is shown as a letter next to the load index value of the tire. In the case of the 116L tire, the “L” represents the speed rating for that tire.
At a minimum, the speed rating of a tire will tell you the maximum speed a tire is capable of supporting while the tire is at its recommended load capacity.
There are tons of speed ratings ranging from A to Y (and even a few below A). Generally, the higher the letter (Y is “higher” than A), the faster the tire is capable of traveling safely.
In the case of the 116L tire, the corresponding speed rating is 75 miles per hour. If you go over that speed, you run the risk of blowing a tire and damaging your rig—not to mention getting stuck out on the highway!
The speed rating of a tire tells you much more than just the speed that your tire is capable of reaching safely, it also tells you about what kind of performance you can expect from the tire.
The speed rating of your tires also effects:
- The maneuverability of your vehicle
- The handling of your vehicle
- Other performance-related concerns like stopping
Your vehicle manufacturer will usually have a speed rating recommendation for your specific make and model to ensure you don’t encounter performance issues.
The “L” speed rating is pretty low. The tire used in this example is designed for rock crawling. I wouldn’t suggest putting an “L” rated tire on your daily driver. Choose a speed rating that works with your needs.
This video has a info on load index and speed rating:
Wide vs. Narrow Off-Road Tires
The width of your tires will affect the traction you get when traveling off-road. The more rubber that touches the ground, the more grip your rig has. Of course, wider tires are also heavier, hurting your rig’s fuel efficiency. They can also be cumbersome to maneuver if they stick too far outside of your vehicle’s wheel wells.
The type of terrain that you plan on driving over will determine whether narrow or wide off-road tires are best.
Wide Off-Road Tires
The wider the tire is, the greater the weight keeping you on the ground. The weight of the tire is spread over a larger surface area, which gives your rig more grip.
Wide tires are well-suited for terrain that “sucks your tires in,” like mud and sand. When you’re looking for off-roading tires built to handle “sinking” conditions, you’ll want a tire width of at least 12 to 13.5 inches.
A popular mud tire is the BFGoodridge KM3 Mud Terrain Tire. This tire has a width of 12.5 inches and a deep, rugged tread, so you can power through even the muddiest terrain.
Narrow Off-Road Tires
Narrow tires are a common choice for rock crawling. Narrow tires don’t stick out as much, making it easier to fit your rig into tight, rocky corridors and paths.
Narrow off-road tires are often called “pizza cutters” for their tall, skinny frame. One of the most popular “pizza cutters” on the market is the Dick Cepek Extreme Country All-Terrain Radial Tire 33×10.5R15. At 10.5 inches wide, they’re about two inches narrower than most off-road tires.
All-Terrain vs. Off-Road Tires vs. Winter Tires
Off-road tires, winter tires, and all-terrain tires oh my! With so many rugged tire options to choose from, how can you tell which is best for you? Let’s take a look at the differences between various tire styles.
All-terrain tires are the perfect blend between on-road and off-road. They’re stronger and treadier than standard street tires but still maintain efficient on-road performance. Tires classified as all-terrain tires provide a balance of performance and grip.
Although they’re not necessarily outstanding in any one category, all-terrain tires are a quality choice if you’re planning on punching through moderately-rough terrain. All-terrain tires are an excellent option for you if you still plan on doing quite a bit of road driving with the vehicle.
Off-road tires are designed to enhance your ability to navigate mud/sand or to crawl over rocks and can be broken down into a few different categories.
Mud terrain tires, abbreviated as M/T, are designed specifically to dig through terrain that would cause other tires to spin out of control.
M/T tires have deep spaces between treads, and the tread blocks themselves are wider than what you see with other types of tires.
Deeper and wider grooves allow the dirt and mud to enter a network of channels that will allow the tire to effectively clean itself of debris as you drive. While that might be great in the mud, the drawback of such an aggressive network of treads is that these tires will wear down much faster than either street tires or all-terrain tires. They also aren’t as efficient (and very loud) when driving on the road.
Tires for Rock Crawling
Another type of tire is the rock tire, which is usually designed with some pretty gnarly-looking treads that are reinforced so that they don’t get punctured by sharp rock edges. The reinforced treads aren’t nearly as compatible with paved roads as all-terrain tires are, so only choose this type of tire if you do a lot of rock crawling.
The BFGoodrich BFG Krawler TA KX is one of the more sought-after tires for rock crawling.
Winter tires have squared-off shoulders, giving them the ability to dig into the snow much better than typical rounded tires. The deep grooves within the treads stabilize grip and traction on snow and ice covered roads. They’re also made of special rubber compounds that are designed to remain soft, even in freezing temperatures.
The Sumitomo Ice Edge Snow Radial Tire contains wide and serrated tread channels. The center treads are shaped like triangles designed to expose more of the tire tread to the road’s surface.
But let’s be honest here. These won’t look nearly as cool on your jeep or truck.
Consider the Rubber Compound
Off-road tires contain different rubber compounds than standard street tires, which impacts the tire’s lifespan.
Off-road tires have a shorter tread life than standard tires. This is because off-road tires use a softer rubber than street tires to give them more grip on rugged terrain. The average lifespan of off-road tires typically fall somewhere between 40,000 miles and 70,000 miles. Generally, the treadier the tire, the shorter the lifespan.
Upgrading Your Rims/Wheels for Off-Roading
Even if the new tires do fit your old rims, standard factory rims might not be able to hold up to hardcore off-road action. When upgrading your tires, you should consider finding new rims for both design and performance reasons.
When looking for new rims, you typically have two choices: aluminum or steel. There are pros and cons to each, so the right decision for you will depend on your preferred overlanding style.
Aluminum alloy wheels, sometimes just called “alloy wheels,” are formed by blending aluminum and nickel. Aluminum alloy wheels are usually the best all-round choice for road driving.
Advantages of Aluminum Alloy Wheels:
- Lightweight, maximizing fuel efficiency
- Capable of withstanding high temperatures
- Design aesthetics
- They come in a wide range of sizes and finishes
Steel Wheels are formed from an alloy of iron and carbon. They’re heavier than aluminum alloy wheels, bogging down acceleration, maneuverability, and fuel efficiency, but they’re also much tougher than aluminum alloy wheels, making them a practical option for off-road vehicles.
Advantages of Steel Wheels:
- Resistant to damage from gravel and rocks
- Resistant to impact cracks
- Generally, less expensive than aluminum wheels
- Can withstand harsh winter conditions better
- Easier to repair
For most hardcore off-road enthusaists, steel wheels are the best choice. They’re much tougher than alloy wheels and easier to repair if you hit a massive bump out on the trail.
Keep Your Off-Road Vehicle Street Legal
Some states and localities have restrictions that may prohibit your off-road vehicle from being used in the streets. This is something you should definitely look into before buying new off-road tires.
The most common restriction requires on-road vehicles have a wheel and tire assembly that sits within the fender. In other words, your tire can’t stick out beyond the fender. In general, a tire sticking out from the fender would have to do with your wheel spacing. If you want a wider wheel, you might need to purchase an aftermarket fender that covers the width of the new wheel.
Your tires are all that connect your overland rig with the ground below. To make sure you have the traction and performance necessary to get to the most remote campsites, you need to make sure your tires are up for the task.
Off-road tires come in a wide variety of shapes and sizes, and there’s no single option that will work for every overlanding style. Think about the size tire that you need for overlanding (and will fit on your rig), the tread pattern you need, and the style of wheel/rim that’ll work best for you. With the right tire, your rig will be able to conquer any terrain—and look good doing it, too!