4WD Tips from Rob Ackland, Red Earth Expeditions No. 4 (Part 1)

Tyres and Tyre Pressure Part 1.

Tyres and tyre pressures

If there is a subject guaranteed to create passionate debate amongst 4WD owners it is tyres and tyre pressures. We get to see all types of vehicles, drivers and tyres over the course of a years training and touring. This experience over many years has allowed us to test, prove and disprove a range of urban myths. So here are our thoughts on the matter.

The first fact is there is no such thing as a puncture proof tyre! So our approach, regardless of tyre type, is to do our level best to reduce the risk of punctures.

Tyre pressures

There are two schools of thought on tyre pressures. The first group pumps their tyres up to rock hard and reckons that will work in all situations. We find that they are the people who most often complain about the number of punctures they experience. We support the second group which lowers their pressures to suit the conditions and, while punctures always remain a possibility, they experience far fewer problems. We use two pressures, regardless of tyre type. In sand we start at 18 psi and then work down if the going gets tougher. But the lowest we go in normal sand driving is 16 psi. If things are really bad then 12 psi is for getting really stuck vehicles out of a difficult situation. Once rescued go back up to 16 psi. Please remember that at low pressures, below 14 psi, there is a chance of rolling a tyre off the rim if you make a rapid change of direction, but these pressures would normally only be used in very soft sand. Once we leave the bitumen and when traveling in rocky country like the tracks of the Flinders Ranges we use 26 psi which seems to offer a nice balance between good traction on shale and rocks as well as a reasonable amount of sidewall flex to lessen the risk of staking a sidewall on a rock. These pressures also help reduce wheel spin providing greater traction but also, with less wheel spin, you are not digging holes in the track. Wheel spin is generally a sign that the vehicle is being over-driven due to a lack of grip or driver skill.

Tyre gauge and compressor

A good quality tyre gauge is a mandatory part of any good four wheel driver’s recovery equipment, along with a compressor. Use the same gauge every time to ensure you are getting constant readings. We have three gauges as someone always forgets theirs; a digital one and two regular gauges, one of which copes with very low pressures which is useful for checking our poly air bags. Remember, if you lower tyre pressures, decrease your speed! With compressors you pay more money for improved capacity and speed. We have two; a Big Red under the bonnet and a portable Bushranger Super Max. Both work hard and reliably particularly given that we would be normally supporting anything from six to ten vehicles for pumping up their tyres.

Stay tuned, next week Rob tells us which tyres he recommends and some important information to consider about tyres before heading Out Back…

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Rob Ackland, RED EARTH EXPEDITIONS