There is a lot of confusion about how and why getting your tyre pressures set properly is critical to getting more out of your 4WD.
It’s a little bit funny that getting your tyre pressures right when you’re heading off-road costs practically nothing, yet it gains so much extra performance out of your tyres. It has three key benefits;
Firstly, it allows the tyre to mould around an obstacle, avoiding a puncture.
Secondly it keeps more tread in contact with the terrain which gives you more traction,
Thirdly, more traction means less track damage due to unnecessary wheel spin.
Because every 4WD, tyre and driver is different, there is no one-size-fits-all solution. With that in mind, here’s a few tricks to help you determine the perfect tyre pressure for every terrain.
To get your tyre pressures set to the most accurate air pressures we recommend using a high-quality tyre deflator something like the Kwiky Tyre Deflator available at 4WD Supacentre showrooms and Approved Dealers.
On the sand, start by dropping your tyres down to about 16psi with your Kwiky Tyre Deflator. If you begin noticing wheel spin or your tyres start digging down, drop a few more PSI out. But remember, once your tyre pressures are that low, you need to drop your speed and avoid sharp turns, or you could peel your tyre right off the rim.
DIRT ROAD TOURING
When it comes to corrugated high-speed dirt tracks, running around the 28psi mark and keeping your speed under 80km/h will help cushion the ride while still maintaining responsive handling. You do need to be careful not to go too low, or travel too fast, or there’s a good chance the tyre will overheat.
18-22psi is usually a good pressure to start with for low-range dirt tracks like fire trails. You need lower pressures to maximise your traction. Caution is required though, because if the tyre or sidewall nudges a rut or rock while you’re running too low, you might end up popping the bead off the rim.
You’ll generally have a higher chance of popping the bead off the rim over rocky terrain, when compared to other terrains, so experimenting between 14psi and 22psi while keeping a close eye on the wheel is your best bet. One downside to low tyre pressures is a slight loss of ground clearance. Take 35in tyres on a GQ Patrol for example. It will loose 10mm of diff clearance for every 10psi dropped.
Mud can be difficult to get right because each mud hole is different from the next. One school of thought suggest a slightly higher tyre pressure of around 22psi, which allows the tyre to slice down through the sloppy top layer and actually bite down into the harder crust beneath. Others believe the bigger your tyre footprint, the more grip on hand, so they aim for a lower pressure of around 14psi.
Depending on the surface below, aim between 18-22psi as starting pressures when tackling water. It’s important to remember that the more air that remains in your tyres, the more buoyancy your 4WD has, and so the greater the chance of it slipping off course in flowing water.
It’s important to know that every 4WD and tyre is different, so the trick is to experiment to find the best results for your 4WD.
THE PERFECT TYRE PRESSURE – GUARANTEED!
The 4psi rule can be used across any vehicle, on any terrain, to determine the best pressure for your tyres and the speed you are travelling. It goes like this…
Starting with cold tyres, set the pressures you think best suits the TERRAIN and SPEED. Go for a drive for about an hour to allow the tyres to warm up, and then pull over and check the pressures again.
If they have gone up by more than 4psi, then the starting pressure was too low and you’ll need to add a couple of PSI per tyre next time. If they have gone up by less than 4psi, then your starting pressures were too high and you could drop a couple of PSI out.
The only thing to keep in mind is that this doesn’t take into account the possibility of rolling the tyre off the rim, so your safest bet is to go no lower than 14psi, unless extenuating circumstances arise.