The right tyre pressure is essential if you’re going to get the best driving performance from your 4×4. Whilst there may be some variation between vehicles, there is a general consensus on the type of pressure that works best in various circumstances. Here we consider the sort of tyre pressure that’s going to work best in urban conditions, off-road, and when driving over more challenging surfaces.
Why does tyre pressure matter?
Tyre pressure has a significant influence on the way in which the vehicle handles. The “springiness” of the tyre, as well as the amount of it that makes contact with the driving surface, has a key effect on fuel consumption, handling, and safety.
Tyre pressures for on-road driving
Usually, we suggest that drivers use the pressures recommended by the manufacturer (these will be available in the driver’s manual). For most 4x4s, tyre pressures for urban or tarmac road driving will be somewhere between 30psi and 38psi. If a vehicle is travelling laden, it’s usually good practice to increase the rear tyre pressure by somewhere between 2-4psi (so if you normally travel empty with 34psi in each tyre, you may wish to increase the pressure of the rear tyres to 36 or even 38 if carrying a load).
Rocky, bumpy surfaces
As a general rule, the rockier the surface, the lower the tyre pressure needs to be. If you’re travelling on a well-maintained, gravel road, for example, you can probably just drop the speed a little, but keep the tyre pressures as they are. If you’re off-roading over extremely rocky terrain, tyre pressures may be better as low as 22pso or 24psi. The increased traction that a lower psi can give needs to be balanced against the sacrifice of speed, and also the enhanced risk of the tyre detaching from the rim.
Most 4×4 drivers are aware of the need to drop tyre pressures if crossing sand (or snow). The best tyre pressure to use essentially comes down to how firmly packed the sand is: the looser the sand, the lower the tyre pressure can be – 16psi may be necessary in soft sand, on a gradient, whilst 22psi may be appropriate for sand that’s more firmly packed. In these types of terrain, driving slowly, with no sudden turns, alongside lower tyre pressures can increase traction and enable progress.
One of the key considerations when embarking on a muddy drive is the depth of the mud. In some cases, the mud will only be a few cm deep, with firmer ground beneath. In these circumstances, a slight drop in psi may be all that’s needed to provide better traction (for example, a drop from 32 or 34psi down to 28 or 30psi). Deep mud may require a steeper drop, to widen the amount of tyre in contact with the road surface significantly.