No matter what kind of vehicle you drive or which tyres you choose, vehicle efficiency and safety are affected by whether your tyres are correctly inflated.
If your tyres are under-inflated, their rolling resistance increases. This means they need more energy or fuel to make them turn. Think about how difficult it is to ride your bicycle with under-inflated tyres. Tyres that are underinflated can reduce fuel efficiency by up to 4% - this is like adding another 8 cents per litre to your fuel costs. In battery electric vehicles, higher rolling resistance will likely affect your range.
Your vehicle’s handling, cornering, acceleration, braking and wet grip are all impaired if your tyres aren’t inflated to the right pressure. If you have under-inflated tyres you’re more likely to have a dangerous blowout.
When your tyres are under-inflated, the contact patch with the road surface is concentrated towards the two outer edges of the tread. This leads to rapid wear on the shoulders, and reduces the life of your tyres.
- Different vehicles need different levels of tyre pressure. You can find the correct pressure for your vehicle on a plate inside the driver's door, the fuel flap or in your vehicle handbook. You can also use our tyre pressure tool.
- Tyres lose air pressure naturally - about 1 to 2 psi per month (3 to 6%). Check your tyre pressure at least once a month and before long journeys.
- Check the pressure when your tyres are cold - so when you’ve travelled less than 3 km.
- Use the free pressure gauges available at most service stations, or there are a variety of affordable pocket gauges.
- Check the pressure in all four tyres and the spare.
Adding extra pressure
If you’re carrying a full load of passengers or towing a trailer or caravan, increase your tyre pressure in line with the vehicle manufacturer's recommendations. If your vehicle handbook doesn’t provide this information, a rule of thumb is to add 4 psi (28 kpa or 0.28 bar) to the recommended pressure.
When you’re checking the pressure, check the condition and tread depth of your tyres. Bulges, lumps or cuts are all signs that your tyre may need replacing. Although 1.5mm is the legal minimum tread depth, the grip of tyres in wet conditions reduces more rapidly once tread is below 3mm.
In-vehicle tyre pressure monitoring systems are becoming more common in new cars. They monitor the amount of air in your tyres and alert you when the pressure falls below a certain level. Look out for this feature when you’re buying a car.