ON-ROAD TYRE PRESSURES
TO figure out a start point when it comes to setting the correct tyre pressures for on-road driving, just look at your vehicle’s tyre placard. But bear in mind that while the tyre placard will list different tyre pressure recommendations for different OE tyre sizes, you might have to adjust pressures to suit aftermarket LT tyres if fitted. The placard will also likely list higher pressures for when the vehicle is carrying a load, and this is an important consideration, especially for 4x4 utes that have higher payload capacities.
If a vehicle is carrying a heavy load, it might be necessary to run higher pressures in the rear tyres than the front. Likewise, a vehicle equipped with a steel bullbar, a winch and driving lights will likely need higher tyre pressures up front than what is listed on the tyre placard. Figuring out the ‘perfect’ on-road tyre pressures to suit your vehicle is often a case of trial and error, and it will depend on how you want your vehicle to behave on the road in terms of ride quality, steering response and handling.
It is important not to go too extreme when adjusting tyre pressures for on-road driving. Go too low and the tyres will flex a lot in the sidewalls and generate too much heat, which can result in tyre delamination, which is essentially where the tyre separates in to its various components. Go too high with pressures and ride quality will suffer through a lack of sidewall flex, and the tyres will also be more prone to punctures.
Pressures also have a big effect on tyre life; overinflated tyres will wear prematurely in the centre of the tread area, whereas under-inflated tyres will wear more on the outside of the tread area. With the right inflation pressures, the tyres should wear evenly across the tread face, assuming the wheels are correctly aligned and balanced.