A few minutes at the beginning of each month can save you money and headaches down the road. How? By doing a simple tyre pressure check. Did you know it’s not the tyres that support the weight of your vehicle but rather the tyres’ air pressure?
So it comes as no surprise that tyre pressure influences many important characteristics of vehicle performance, such as driving comfort, directional stability, cornering and braking grip, plus general handling behaviour.
Tyres lose air pressure naturally at a rate of around 1-2 psi (pounds per square inch) per month, so it’s important to monitor tyre pressures regularly to ensure optimal performance.
What are my recommended tyre pressures?
The tyre pressures specified for your vehicle are agreed to by the vehicle manufacturer and the tyre producer. The psi or kPa (kilopascals) is based on your vehicle’s total weight and size, towing weight capability, and recommended tyre size. These pressures are set to keep you safe and comfortable on the road so it’s important to follow them.
But how do you know what the recommended pressures are? They can usually be found in your vehicle handbook, inside the fuel filler flap, or on the driver's door post. If you can’t find the manufacturer’s recommended pressures anywhere, you could ask your local tyre shop for a recommendation or use the general rule of 30-32psi in the rear and 32-34psi in the front tyres. These recommended tyre pressures are based on “cold inflation pressure”.
Why do I need to check the cold inflation pressure?
Gas expands when heated and contracts when temperatures decline. This means that you should check your tyre pressures in the morning before the ambient temperature rises, before exposure to direct sunlight and of course, before driving the vehicle.
Daily temperatures rise and fall between seasons which cause tyre pressures to fluctuate - 1.5 psi for every 10C. As temperatures drop in autumn and winter, it’s especially important to check tyre pressures. In some colder areas of New Zealand, your tyres could experience a drop of a few psi. Add this to a slow pressure reduction of non-regular inflation checks and you have potential for very under-inflated tyres, which affect traction, handling and durability.
This fluctuation throughout the year leads to the recommendation of checking your tyre pressures at the beginning of each month and before long road trips where the additional load may require increased tyre pressures.
How to check tyre pressure
- Before you begin to assess your tyres, make sure they’re cool. Park your car on a flat surface to get the most accurate reading.
- Remove the valve cap and connect a tyre gauge or service station inflator to get the correct reading.
- If you determine that a tyre need air, insert the pump into the tyre valve and fill it to its recommended pressure level.
- Once the air has been adjusted to the proper level, replace the cap and check the remaining tyres in the same fashion.
Most service stations have a free tyre inflator connected to an air compressor than can display the pressure in psi and kPa. They are pretty simple to operate and should have step-by-step instructions on the front facia.
Checking your tyre pressure is a quick and easy process that has many long term benefits. Your fuel economy will be better, your tyres will last much longer and most importantly, you’ll be safer on the road.