Knowing how to read and understand tyre pressure is key to keeping your car safe, fuel-efficient, and comfortable to drive. This guide explains what PSI, Bar, and kPa readings mean, where to find your car’s ideal pressure, and how to ensure your tyres stay in perfect shape year-round.
As a driver, you will know when your tyres are running low on pressure. Not only does it affect the shape and look of the tyre, but it impacts the performance of the vehicle, the comfort of the journey, and how safe the vehicle is to drive.
Tyre pressure falls slowly over time and with continued use or can suffer a sudden drop owing to damage or a crack appearing in the rubber. Luckily, restoring a tyre to its optimum pressure is quick and easy, provided you have access to both the right equipment and the information you need to decipher the different readings.
Tyre pressure machines can be found in most major fuel stations across the UK. It’s the small unit that accepts coins or a card transaction, charging usually around £1 for 5 or 10 minutes of access to the air. Drivers need only set the machine to their ideal pressure rating and then fix the nozzle to the valve of each tyre – adding (or removing) air as necessary to reach the right reading.
Sounds easy, right? And it is. As long as you know how to interpret the readings.
The Different Types of Pressure Reading
Tyre pressure can be read using one of three different units.
PSI, Bar, and kPa, are all used readily across the UK – though some units are more common than others.
- PSI stands for ‘Pound force per Square Inch’ and uses the imperial system that’s rife across the UK.
- Bar is a unit that measures atmospheric pressure and is used across Europe.
- kPa is a kilopascal and measures the strength of the pressure in hydraulics.
Where Will You Find the Optimum Pressure for Tyres?
The ideal pressure for your car tyres will be based on the vehicle. Therefore, the information regarding optimum tyre pressure can be found on the inside wall of the driving side door.
Drivers will find a chart that tracks different vehicle weights and passenger numbers, with the ideal tyre pressure to handle that weight listed.
Conversion charts exist across the internet, which allow drivers to convert the reading from one unit to another for ease. However, you will find that most public machines for adding more pressure to tyres will allow you to set the unit to whatever one correlates with your vehicle.
In short, it doesn’t really matter which unit you use to measure your tyre pressure. What matters is that you use the correct conversion information if you do decide to change units, or make sure that the pressure machine is fixed to the correct unit before adding or removing air from your tyres.
