Running the right tyre pressure makes a noticeable difference to how your vehicle handles, how evenly your tyres wear and how much heat builds up while driving. When pressures suit the tyres, the vehicle and the conditions, tyres last longer and perform as they should. When pressures are wrong, wear accelerates, handling becomes unpredictable and the risk of tyre damage increases.
Tyre pressure is not a single set number that works everywhere. It changes depending on tyre size and construction, vehicle type, load, speed and the surface being driven on. This guide explains how tyre pressure works in everyday driving and how to adjust pressures for Australian road and off‑road conditions.
Checking Tyre Pressure
All tyres lose small amounts of air over time, which is why tyre pressure needs to be checked regularly. Checking at least once a month helps pick up gradual pressure loss, while checking before trips and during extended travel helps ensure tyres are starting the day at the right pressure.
Before driving, tyre pressure should be checked while the tyres are cold. Once the vehicle is moving tyres heat up through friction and flexing, which increases the air pressure inside them. Letting air out at this point can leave the tyre under‑inflated once it cools.
When pressures are being deliberately lowered for off‑road driving, adjustments can be made while tyres are warm. In these situations, tyres should always be re‑inflated once sealed roads or higher speeds are resumed.
Because a tyre can lose a surprising amount of air without looking flat, visual checks are unreliable. Accurate readings should always be taken using a quality tyre pressure gauge.
How Tyre Pressure Affects Wear and Handling
When tyres are run at lower than recommended pressure, they flex more as they roll. This extra movement creates heat inside the tyre and places more load on the outer edges of the tread. Over time this leads to uneven wear and a noticeable reduction in tyre life. Steering response and cornering stability are also reduced, while rolling resistance increases and fuel economy can suffer. A pressure loss of around 6 PSI can represent roughly 20 percent of the recommended pressure and also reduces the tyre’s load‑carrying capacity.
Excessive tyre pressure creates different issues. Load is concentrated through the centre of the tread, which leads to uneven wear and reduces the tyre’s ability to absorb impacts from potholes or debris. Ride comfort is also affected, as the tyre becomes firmer and less compliant.
Keeping tyre pressure within the correct range allows the tread to wear evenly, maintains grip and helps control operating temperatures.
Choosing the Right Tyre Pressure
How much air a tyre needs depends on what the vehicle is doing at the time. Adding load means the tyre has more weight to carry, so pressure needs to increase to match. That increase has limits though, and pressure should never exceed the maximum shown on the tyre sidewall.
The type of road or track also plays a part. Smooth bitumen allows higher pressures, especially when towing or carrying gear. Rough roads and uneven surfaces place more stress on the tyre, where slightly lower pressures and slower speeds can help reduce damage and heat build‑up.
Adjusting tyre pressure with load, speed and surface in mind helps keep tyres working as they were designed to.
The 4 PSI Guideline for Sealed Roads
For bitumen driving, the 4 PSI guideline can be used as a reference to check whether tyre pressures suit the current load. Tyres should be inflated when cold to the pressure listed on the vehicle’s tyre placard, and that cold pressure noted. After driving for 20 to 30 minutes at normal road speeds, pressures can be checked again.
A warm pressure reading around 4 PSI higher than the cold pressure indicates the tyre is operating within a normal temperature range. For most 4WD and light truck tyres, a rise of around 6 PSI can be used as a guide.
If the pressure increase is greater than this, excessive heat may be building up, indicating more air is required. A smaller increase suggests the cold pressure may be too high.
Download a copy of our 4WD Tyre Pressure & Tips Guide so you can record and repeat pressures that work for your setup.
**This guideline is intended for sealed roads only. On rough or corrugated roads, increased tyre flex can cause pressures to rise more quickly, making this method unreliable. Older vehicle placards showing pressures below 30 PSI should also be treated with caution, as these were sometimes specified to improve ride comfort rather than tyre durability.**
Lowering Tyre Pressure for Off‑Road Driving
As tyre pressure is reduced, the tyre’s footprint becomes larger, spreading the vehicle’s weight over a greater area. This improves traction and allows the tyre to conform more easily to uneven surfaces.
On sand, a larger footprint helps prevent tyres from digging in and allows the vehicle to stay on top of the surface. On gravel, mud and rocky terrain, lower pressures improve grip and reduce sharp impact loads.
Whenever tyre pressures are lowered, vehicle speed needs to be reduced as well. Sudden steering inputs and wheel spin increase heat and accelerate tread damage. Once conditions allow, tyres should be re‑inflated before returning to sealed roads or higher speeds.
Tyre Pressure Guide for Different Terrain
*SAFETY NOTICE: All pressures stated are based on an average range of sizes, not a specific size. Tyres must be re-inflated to proper levels once your vehicle is returned to normal road applications and conditions. All pressures stated are suggested for light truck construction tyres only and should not be advised to any person driving on passenger or light duty construction tyres. You must consult your Authorised Cooper Tires Stockist to get the right pressure for your specific vehicle’s weight and tyre size.
Lowering pressures may be necessary to get your vehicle through an extreme section of terrain or reduce tyre damage in off-road conditions. However, lowering tyre pressures below the manufacturer’s recommended pressure for your vehicle is at your own risk and judgement and doing so could cause over-heating and long-term tyre damage. So, you must drive slowly over obstacles and re-inflate your tyres to proper levels once your vehicle is returned to normal road applications and conditions.
Bitumen 32-38 PSI*
For sealed roads, tyre pressures should follow the recommendations on the vehicle’s tyre placard. When carrying heavy loads or towing, higher pressures may be required to support the additional weight. Pressures should always remain below the maximum shown on the tyre sidewall.
Sand 18-26 PSI*
Sand pressure depends on the depth and coarseness of the sand and the grade being driven. Lower pressures increase the size of the tyre’s footprint, improving flotation and helping the vehicle stay on top of the sand rather than digging in. Enough momentum is required to maintain progress, but speed should be reduced and steering inputs kept smooth.
Higher pressures may be required when carrying heavy loads. Sand conditions can change quickly, and sand generates constant resistance, which builds heat in tyres, driveline components and engines. Regular rest stops may be required to manage temperatures.
Fast / Smooth Gravel 28-34 PSI*
On faster gravel roads, running pressures that are too low can reduce steering response and vehicle stability, particularly at speed. Higher pressures may be required when the vehicle is heavily loaded.
Corrugated roads generate heat quickly due to increased tyre flexing, so speed should be reduced to help manage temperature build‑up.
Slow / Rough Gravel 26-32 PSI*
Pressure selection depends on how slow the vehicle is travelling, how rough the surface is and the load being carried. Lower pressures increase the contact area between the tyre and sharp gravel edges, which helps reduce tread chipping.
As pressure is reduced, vehicle speed should also be reduced to limit heat build‑up. Heat in the tyre belts is not always obvious by touch, so speed management is important.
Mud 22-28 PSI*
Mud pressure depends on mud depth, consistency, slope and what lies beneath the surface. In some situations, pressure reduction may not be required.
Thick mud with a loose base may benefit from lower pressures, avoiding wheel spin and maintaining steady momentum. Watery mud with a solid base may allow higher pressures, but speed should always be kept low to maintain control and avoid damage. Medium‑consistency mud requires a balance of traction and momentum while minimising track damage.
Higher pressures may be required when carrying heavy loads.
Rocky Gravel / Rocks 22-28 PSI*
These pressures assume very slow driving, often in low range, with minimal heat generation. Lower pressures allow the tyre to better envelop rocks and obstacles, improving traction and reducing impact damage.
Pressures below around 20 PSI increase the risk of pushing the tyre off the rim. For most vehicles, 22 PSI is considered a practical minimum. While lower pressures reduce overall damage risk, they can increase the chance of sidewall damage, which can be managed through careful wheel placement and reduced speed.
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