What should my tyre pressure be while off-roading?

When driving on a tarred road, the vehicle manufacturer will provide the optimum tyre pressures for a general ride and handling of the vehicle and can be found in the vehicle's user manual or as a sticker in the door or fuel flap of the vehicle.

When driving in off-road conditions with a 4X4 vehicle, one question always arises: ‘What should my tyre pressure be under these very different conditions for optimal performance?’

When driving in off-road conditions there are three factors to be considered, traction, comfort and heat build-up.

When the inflation pressure is decreased with constant load, the speed needs to be reduced to minimize heat build-up, excessive heat can damage or destroy tyres.

By decreasing inflation pressure in off-road conditions, one increases the level of traction as the footprint of the tyre lengthens and the comfort is improved due to more tyre deflection. The lower the inflation pressure, the more the footprint extends with higher levels of traction, however, speed must be decreased to reduce heat build-up.

See below for a guideline on inflation pressure based on speed:

Example:

If your vehicle manufacturer has specified an unladen inflation pressure of 250 kPa and laden inflation pressure of 350 kPa and the vehicle is half loaded, the recommended pressure is therefore 300 kPa on a tarred surface. If the driver wishes to drive on a gravel road at a maximum speed of 80 km/h, the inflation can be dropped by 50% of the standard pressure, in this case from 300 kPa to 150 kPa.

Be sure to always reinflate your tyres when transferring back to a tarred surface and increasing the speed. It is important to always adjust the pressure to changing driving conditions. If you do not increase the tyre pressure when moving from gravel to tar, the stability of the tyres could be impaired, or it could result in with an increased braking distance and excessive heat build-up.