Tyres are the only thing that connects you to the road when you’re driving – as such, correct tyre pressure means your car handles as it should, brakes as it should, and even uses the right amount of fuel. On the other hand, an incorrect car tyre pressure can mean poor fuel economy, poor tyre life, and dangerous handling.
In this guide, we’ll explore tyre pressures in more depth – explaining how to find the correct tyre pressures for your car, why it’s good to have your own tyre pressure gauge, and what the correct pressure means for your car and your bank balance!
How to check your tyre pressure.
Before we get into anything else, it’s useful to understand what pressure is in your tyres right now. You’ve got a couple of options for how to do this.
Option 1: Local Service Station
Go to your local petrol station and you’ll almost always find a machine that you can use to inflate your tyres. You might need to drop a 20c coin in – but in exchange, you’ll get a few minutes of air through the air hose to make sure your tyres are just right.
When you put the air hose onto the tyre valve, the read out on the machine will tell you what the current pressure is. Then, it’ll add or remove pressure based on what you’ve set the machine to.
Option 2: Tyre pressure gauge
Checking tyre pressure at home is a great idea – so you can pick up your own gauge for a few dollars. Most are digital, giving a clear LCD read-out of your car’s tyre pressure – but some are analogue, with a metal bar that slides out like a ruler to show how much air is inside.
Tip: Check your tyre pressure when tyres are cold
Temperature affects the air that fills your tyres. For this reason, it’s better to check cold tyres. This means tyres that have no been driven for more that a few kilometres.
If they warm up on a longer journey, it can cause the read-out to drop slightly.
What are your recommended tyre pressures?
Each car is a slightly different weight – so the amount of air needed in your tyres will vary. As you can imagine, a 7.5 tonne truck needs more air in the front and rear tyres than a small city car.
Car manufacturers will give you the ideal tyre pressure for the vehicle in a couple of different places. You’ll usually find tyre pressure charts stuck to the inside of one of the door pillars. These are referred to as a tyre placard and will give ideal pressure figures for the car depending on the conditions and the number of passengers you’re carrying.
The same is true for your vehicle’s handbook too. They will also give a minimum and maximum pressure guide.
What are some typical tyre pressure figures?
Most passenger car tyres are designed to be inflated to between 31-35 ‘pounds per square inch’ (usually referred to as ‘PSI’).
If you have an especially low tyre pressure – usually under 20 PSI – you’re running the very real danger of a ‘blow out’ meaning a tyre that splits or comes off the rim when you’re driving.
You shouldn’t even try to drive a short distance on a tyre that is this low as most tyre failures happen as a result of low pressure.
It’s worth noting that you’ll often need to significantly increase pressure if you’re towing a trailer – so be sure to check your handbook if this is the case.
Problems with over-inflated tyres
Higher inflated tyres often result in the following issues:
- Reduce your area of contact with the road – reducing grip
- May result in reduced braking efficiency
- Make the tread wear unevenly so that the centre of the tyre degrades more quickly
- Less predictable handling
- An unpleasant ride because the tyre cannot “soak up” the bumps
Problems with under-inflated tyres
One of the main reasons for tyre failure is under-inflated tyres. Low pressure causes the tyre to contact the ground too much, creating friction and drastically shortening tyre life.
- Rolling resistance may be increased by under-inflated tyres
- Increased fuel consumption since the engine must work harder owing to rolling resistance
- Creates uneven tread wear, causing the tire’s edges to deteriorate more quickly
- Reduces braking efficiency
How often should you check tyre pressure?
In an ideal world, you’d check your tyre pressure before every journey.
However, we realise that checking before every journey usually isn’t practical – so instead, be certain to check your tyre pressures at least every two weeks and before long journeys.
Also, be sure to keep an eye on your tyre pressure warning light. This is an orange warning light shaped like a tyre with an exclamation mark inside it. This feature is fitted as standard to all cars after 2012 – so will let you know if you have a pressure problem before it becomes dangerous.
Matt is the founder of Autohero.com.au and has been hooked on cars and repairs ever since childhood. A veteran in automotive since leaving school, Matt has completed his trade as a panel beater and is across all things with wheels.
His first car was a 1967 FORD XR Wagon followed by a string of collectable Holden’s.
Have a question for Matt? leave a comment below.