Air Pressure Guide For All-Terrain Tires

Pressure can really impact the performance of all-terrain tires, and optimal PSI values can do wonders for the traction on rocks, gravel, sand, and even mud. Decreasing air pressure basically increases the contact patch which then translates in to a better grip and stability on all types of rugged terrains.

Being a tire engineer, I can tell you that the air pressure of around 18-22 PSI for rocks, 16 to 20 PSI for muddy terrains, and 10 to 14 PSI for sand, has always worked for me. Though it’s recommended that you experiment a little bit with your tire size. Though keep in mind that the more your vehicle weighs, the more pressure PSI values you need. Adjust air pressure accordingly.

Following you’d find all the terrains, and what pressure to keep on them for maximum traction.

For Roads/Pavements

Starting with the roads, I would recommend that its best to set the air pressure as as stated on your vehicle’s tire placard.

This “placard” is mostly located on the driver’s door jamb, or in the glove box. Though if you still can’t find it, just check out in the owner’s manual.

Though still, as a general rule, keep in mind that for most 4X4s, as the weight increases, you should consider increasing the pressure as well. If there is no extra weight on, you can run your 4X4 with recommend pressure.

Let say for example that the recommended pressure is 30 PSI. Now if there is no extra cargo, and there is nothing to tow, you should keep 30 PSI in all tires.

Though if you are carrying some extra weight, consider running your front tires with 32 PSI and rear ones with 36 PSI.

This is basically done to avoid all kinds of wear patterns, meaning, if your tires are over-inflated, then they would wear more in the middle part of the tread, and similarly if the pressure is lower, the sides of the tire would wear more compared to the center. And this uneven wear causes a lot of issues.

Also keep in mind that if you are traveling in summer, with a lot of heat, and you have a long way to go, then lowering air pressure slightly from the recommended value is better. As a rough estimate, you can say that every 10° Fahrenheit change changes about 1 PSI of pressure, in LT sizes.

For Dirt and Gravely Roads

When it comes to gravel filled roads, it can either get pretty smooth, or get harsh with sharp biting stones and dirt particles.

For smooth well graded surface, you can keep the similar pressure that is recommended for your vehicle (as I explained above). Though if the track is rougher, consider this.

First ensure your speed and load values. The higher the load/speed, the more generation of heat, so that means higher the pressure.

So its recommended to lower your pressure here by almost 4 to 6 PSI depending on your tire size. For example if you are running 30 PSI, consider lowering it down to 26 PSI. And if you run 40 PSI on roads, consider lowering it down to 34 PSI.

This would improve the overall flexibility of your tires, and avoid tread damage, (though you do get cut resistant rubber with all-terrain tires).

For Rocky Terrains

On rocks lowering air pressure can do wonders for the overall traction and climbing abilities. That’s because with it, the lugs get to flex more easily and the bend again the terrain, grabbing and pulling.

And besides enhancing the tire’s footprint, it also protects the sidewalls from getting punctured from all kinds of sharp impacts.

But how low to go here? Well, if you are crawling rocks with a turtle speed, nice and easy, consider dropping tire pressure up the range of 18 to 22 PSI.

Though keep in mind, that if you don’t have rim locks, going this low on pressure means you have to keep a lighter foot on the throttle (and steering wheel too). That means no sudden jerking movements. As this can cause the tire to slip off the bead.

Overall its generally still safe if you don’t go below 15 PSI (again if you don’t have a bead locker).

(Recommended Read) Are all-terrain tires good on rocks: https://tiredriver.com/are-all-terrain-tires-good-for-rocky-terrains/

For Muddy Terrains

On mud, the ideal air pressure to keep depends on the type of the muddy terrain. So I am going to discuss from least to most aggressive.

On lighter muddy track (which is not too deep, and where you can see clearly), its recommended to have tire pressure between 20 psi and 25 psi. This much is enough for traction, and avoiding rim slipping off.

For thicker terrains, where tires sink in, knee deep, it’s best to stay under 22 PSI. That’s because it would provide the tire with more footprint and as a result it would tend to float in a better way.

Basically main thing to note here is the composition of the mud. Is it softer or harder? If its softer, lowering the air pressure would be beneficial. Otherwise don’t lower the air pressure too much so that lugs can flex effectively.

Moreover, its best if you can avoid thicker parts of the muddy tracks. Just go straight through the middle where mud is already cleared up a little bit (by other vehicles that went before you).

(Recommended Read) Are all-terrain tires good on mud: https://tiredriver.com/are-all-terrain-tires-good-on-mud/

On Sandy Terrains

On sand lowering air pressure is a must. That’s because you want maximum floating on this type of soft terrain, and digging here is the worst enemy of traction.

But how much air pressure to lower down depends on the softness of the sand. As it can be a sand on the beach, a sandy terrain which is wet, or a completely dry and soft/deep sand (which is the most challenging).

Let’s consider the beach first. Here its recommended to lower the air pressure down to 18 PSI, so that the tire lugs can have ample tread print and you can float without any issues. (This goes for dry sand on beach).

If the sand is wet, and that would mean it’s also not as soft, you can go slightly above, though keep it lower than 21 PSI. The higher pressure here basically offers the same king of flexing that you’d face on softer terrain running at 18 PSI.

Lastly talking about deeper dry sand, consider going below 17 PSI.

Though its recommended that you don’t go below 15 PSI if you are new to sandy dunes. But if you have some kind of experience you can consider going as low as 13 PSI for traction, and can even consider going single digits for recovery if you are stuck.

It’s best if you install bead-lockers on your tires though. As with them, its much more easier.

(Recommended Read) Are all-terrain tires good on sand: https://tiredriver.com/are-all-terrain-tires-good-on-sand/

Things to Check

Well first things first, you should know what your vehicles recommended air pressure is, so you can adjust the pressure accordingly.

And speaking of which, ensure you have a good enough air compressor, a gauge, and extra valve cores when heading out on the trails. You should also keep one extra just in case.

Furthermore, while moving on trails, keep on adjusting tire pressure frequently, though a vehicle with TPMS would be a great alternative to this (where pressure monitors are already installed on all tires, and you get real time pressure monitoring).

Also keep in mind that tires can lose pressure over time, up to 1 psi per month, and 1-2 psi for every 10-degree drop in temperature, just adding for your info.

Conclusion

When it comes to all-terrain tires, air pressure plays a crucial role in ensuring safety and performance on different types of terrain such as rocks, mud, sand, gravel, and paved roads.

And according to my experience, on rocky terrains, consider keeping air pressure between 18 and 22 PSI. For mud, 17 to 20 PSI, and for sand, below 16 does great.

But make sure you know your tires first, and their capability along with size and everything. You can contact me for more help.