Why should I lower tyre pressure when driving off-road?
Should you lower tyre pressure when driving off-road? The short answer is: Yes.
There are two main things to keep in mind about tyres:
- keep the adequate tyre pressure for the right surface – whether you drive on sand, mud, dirt or bitumen lower the tyre pressure to the conditions.
- monitor tyre pressure while you driving the car – we fully covered this topic already, please read – Why monitor tyre pressure.
In this article, we focus on explaining why lowering pressure in your tyres is important, what are benefits of doing it and how to inflate and deflate the tyres.
Why the right tyre pressure is important?
While you drive the car the only thing that touches the road surface is the car tyres. The pressure in the tyres is directly related to how your car steer, accelerate and brake.
Let’s break down why correct tyre pressure is important.
Better Traction
When driving on bitumen there is no problem. You should keep the tyre pressure as per your car specification. The real challenge comes when you go off-road and start driving on dirt, sand or mud.
Many 4WD drivers don’t bother to lower tyre pressure on off-road tracks, but that’s a mistake.
Lowering tyre pressure on dirt roads to 28 PSI gives the car better traction and less probability of tyre puncture. Enabling a high range 4×4 mode will give even more traction.
Getting on sand is a different story. There is no issue driving on hard beaches (except the soft entrance sometimes), but driving on soft, deep sand without lowering the pressure can cause your car to sink to the sand and get stuck.
On deep sand, you should always lower tyre pressure to at least 15 PSI. This will create a wider tyre footprint and easy manoeuvrability.
Less Punctures
Lowering tyre pressure on dirt, or rocky tracks gives the car a cushioning effect making it less probable that sharp rocks will cut and damage the tyre.
Less Wear
When you drop tyre pressure you increase the tyre footprint. While you lower the pressure on the dirt and sandy tracks you should immediately restore it when going back on the bitumen.
Driving fast on bitumen with lowered tyre pressure will cause more wear and will lessen tyre longevity.
Better Comfort
We talked already about the cushioning effect. Let’s break it down by the surface you drive on.
Dirt roads and rocky tracks – with lower tyre pressure you will get through the corrugations or rocks more comfortable. Don’t get me wrong – you still feel it, but significantly less if you did not drop it.
Sand tracks – the main reason to drop tyre pressure on sand is to have better traction, but you will also feel a big comfort difference while driving.
Fuel Economy
Having the right tyre pressure is directly related to the fuel economy of your car. Having underinflated tyres increase fuel consumption by around 5%.
Tyre Longevity
Having your tyres inflated properly respective to the surface you drive on will increase the tyre’s longevity in the long run.
Another important factor is wheel alignment. Correct wheel alignment helps your tyres perform properly and wear evenly.
What are the symptoms of wrong wheel alignment?
- the car is pulling to left or right
- uneven tyre wear
- noisy steering
What is the right tyre pressure in a standard 4WD Vehicle?
The right tyre pressure is strictly related to the surface you drive on. The bitumen tyre pressure of your 4WD should be kept as per your car specification. Usually, it is about 35 – 40 PSI, but if you tow a camper trailer or caravan it could be even 45 PSI.
Conversely, when going offroad you should adjust the pressure as per the below table.
| Surface | Tyre Pressure |
|---|---|
| Dirt Road | 28 – 30 PSI |
| Dirt Road (corrugations) | 23 – 25 PSI |
| Rocky off-road track | 18 – 22 PSI |
| Beach driving (firm) | 18 – 22 PSI |
| Deep sand | 12 – 15 PSI |
| Mud | 15 – 20 PSI |
The above tyre pressure is just an example. The best option is to always check your tyre specification as some brands may have slightly different recommendations.
Should I increase tyre pressure when going back on bitument for a short time?
If you mostly drive on dirt roads and occasionally happens there are bitumen sections, you don’t need to increase the tyre pressure as it would be painful to do it if you have many off and on-road sections.
Instead, when going on bitumen, try not to drive to the full allowed speed and keep it below 80 km/h.
Tyres create friction and they heat up during driving. If you drive with lower tyre pressure and high speed, the temperature increases and this can damage the tyres.
A good example of off and on-road sections is a road to Weipa that we did last year. There is a consistent change between dirt roads and bitumen. We lowered the pressure to 28 PSI and kept it that way to Weipa.
Tyre footprint comparison
Many beginners 4WD drivers think that when you lower tyre pressure in the car, the tyre footprint gets wider. Not really. It is only an illusion when you look from aside. In reality, while tyres have less air the footprint gets longer like in the below image.
How to deflate tyre pressure?
Deflating tyre pressure is much faster than inflating it. The quickest way to do so is by using a tyre deflator like OZTrail Rapid Tyre Deflator or Bushranger Tyre Deflator & Gauge.
In a matter of seconds, you will be ready for your off-road track.
How to inflate tyre pressure?
Inflating the tyres is a longer process (unless you arrived at the fuel station) as you have to use an air compressor. These devices are pretty noisy but having one in your car is a good idea if you are going off-road.
There are many brands to choose from and the prices are between $150 to $400. One of the key things when choosing one is to check how fast they inflate a tyre. If you just do occasional offroading you can select a cheaper brand as you won’t be using it that often.
We use Mean Mother Maxi 3 Air Compressor and we never had any problems. Another good option is Bushranger 12 V 150 PSI Max Air Compressor.
How to increase tyre longevity?
When you drive your car it is not easy to notice when the tyres are getting flat or you have a nail in a tyre. Driving on a flat tyre will damage it almost instantly. So, how to know if there is not enough air in the tyres?
Tyre Pressure Monitoring System (TPMS) is a device with up to 8 sensors that allows you to get temperature and pressure readings from inside your car while you drive the car.
By having one, you can almost immediately react if something goes wrong with the tyres.
Why should I lower tyre pressure? – Summary
There are many myths about airing down tyres when going off-road. You still find many 4WD drivers who think it is pointless to do it as they drove their whole life without any problems.
The rule of thumb is to always lower tyre pressure when going off the bitumen. By doing that, you get better traction, less wear and punctures and you increase tyre longevity.
When you have on and off-road sections in your path, you don’t need to inflate and deflate tyres all the time. That would be very tiring. Instead, drop it to 28 – 30 PSI and when you are back on bitumen, don’t drive faster than 80 km/h.
I hope this article helped you understand why lowering tyre pressure is crucial when going off-road.
If you have any questions feel free to drop a comment.
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4WD Equipment Checklist
GPS Navigator or compass
Maxtrax – if you get bogged, you can use it for additional traction
Tire Deflator – deflate tires quickly when going on dirt or 4WD
Air Compressor – inflate tires quickly after going back on bitumen (we use MM)
Tire Repair Kit – to fix the tire by yourself when you don’t have access to the tire shop (we use Oztrail)
UHF Radio – for communication with your mates and in emergency
Full Recovery Kit (with Dampener Blanket) – must-have if you are going on real off-road
High Lift Jack – useful if you do serious 4WD tracks
Shovel – useful if you get bogged, also good for campfire cooking
Fuel funnel with water filter – additional protection when fueling up in dodgy places
