What benefits does altering your tyre pressure have?

Typically, when driving off-road, more grip can be had by lowering your tyre pressures. Lowering tyre pressures results in the tyre ‘bagging out’ and making contact with the ground over a larger area.

More contact area means a tyre is less likely to sink into soft surfaces like sand, dirt or shallow mud. 

It’s important to note that if you’re facing mud with a solid base, you’d likely be better off leaving your tyre pressures up so your tyre will sink down to make contact with the harder terrain.

Over rocky and irregular terrain, a tyre with less pressure can conform to the terrain and ‘wrap around’ rocks, providing much more contact area and therefore, grip. Lower pressure tyres will have less tendency to suffer puncture damage to the tread face as the rubber will have more ‘give’ in the event of a sharp stick or rock.

It’s worth noting that at low tyre pressures, tyre sidewalls can ‘bag out’ and stick past the tread face, which will put them at marginally more risk of tearing or snagging rocks, sticks or other obstacles.

Controlled deflation of the tyre

It’s no good just unscrewing the valve cap and sticking a screwdriver or a stick in your valve to guess what your tyres are getting down to, although that method works in a pinch.
A set of Staun-brand tyre deflators

A simple set of tyre deflators can be purchased to lower your tyres to a preset level.

A common and popular method of deflating the tyres on your 4WD is the use of pre-set screw-on tyre deflators like the Staun branded set above. They work by screwing onto the tyre valve and gradually releasing air pressure until the pre-set pressure is reached. 

Four individual deflators are set to the same pressure and one screwed into each of the vehicle’s tyres. It is recommended that you check the tyre pressure with an accurate gauge to verify the deflators are set to your desired pressure. Checking is also recommended after adjusting the deflators. It’s our experience that you’ll have to set each of them from when you purchase, so set aside a bit of time for that before you use them.

Screw-in pre-set tyre deflators are easy to use and generally reliable but their distinct disadvantages are that you don’t know exactly what pressure you’ve deflated down to, and you can’t adjust that for the terrain you’re facing, plus the speed of deflation is quite slow. This is especially noticeable when you need to reduce the pressure by a large amount, which brings us to:

Ain’t nobody got time for that.

If you’re not the type to stand around waiting for tyres to air down, the solution is to use a fast tyre deflator.

These work by screwing onto the tyre valve and then a second, internal mechanism removes the valve core enabling a large volume of air to be removed quickly. The deflator has a gauge so you can stop deflation once your desired pressure is reached. The deflator then re-installs the valve core and you can then unscrew the whole deflator unit from the tyre valve.
Rapid air deflator showing 32 psi of pressure in tyre

Rapid deflators actually remove the restrictive valve core for speedier alteration of tyre pressures.

The real benefit of this design is that you can easily set your tyres to a pressure suitable for whatever the terrain requires, as well as there is only one device to look after and keep track of, rather than 4 individual deflators, like with the individual deflators mentioned above.

Every vehicle will have different air pressure requirements based on driving style, weight distribution, tyre width and pattern as well as other factors, but check out our other articles here and here to read more about tyre pressures and to find out about what pressures you might want to try starting with.

You don’t have to choose just one.

It’s relatively common to have more than one type of deflator for different scenarios, with the variety of options never taking up too much space or weight in the vehicle.
It’s up to you to decide which type of deflator suits your needs and setup more, just remember to have the equipment or a plan in place when it comes time to air back up to tyre pressures more suitable for high speeds or on-road use.