For most of us, checking our tyre pressure is the last thing on our minds. They'll check it at my next MOT anyway, so what's the point?  

Well, poorly maintained tyres can lead to significant, unexpected garage bills. Bills that could have been avoided. Poorly maintained tyres can sometimes lead to breakdowns and even severe collisions.  

In this guide, you'll learn how often to check tyre pressure, why it's so important, and how to check the tyre pressure measurements. Let's dive straight in. 

How often should you check tyre pressure? 

Every month! 

That’s right, you should be checking your tyre pressure monthly. Always check when the tyres are cold and before you’ve made any journeys. Hot, or even warm, tyres may give false readings.   

How to check your tyre pressure? 

At a petrol station, with a dealer, or with a portable compressor.  

Most drivers choose to check at a petrol station as this is easier and has an inflation zone. However, a portable compressor is good for those who want to check their tyre pressure from home. 

How to check your tyre pressure on a tyre: Quick steps 

When checking your tyre pressure, use a gauge in the same unit of measurement shown in your car’s handbook. Three common measurements are used for tyre pressure: PSI, BAR and kPa.  

1. First, remove the valve dust cap from the tyre valve, place the pressure gauge on the valve stem, and press it down evenly.  
2. Next, check the reading on the pressure gauge to see if you need to inflate or deflate your tyres.  
3. To inflate, use a suitable pump and add small amounts of air at a time.  
4. To deflate, open the pin on the valve. You should be able to hear air releasing. Make sure to keep an eye on the gauge when inflating and deflating.  
5. Check all four tyres, including your spare. You never know when you might need it. 

Follow these steps and you won’t Google “how to know tyre pressure” ever again! 

When should you check your tyre pressure? 

When the tyres haven’t been driven or have been driven rarely. 

When you drive, the tyres heat up, and their pressure rises. So, if you check your tyres after log drives, they’ll likely feel over-inflated, and you might (accidentally) adjust them wrong.  

The rule of thumb is to only check tyre pressure measurements after a 2 km (or shorter) drive. This gives an accurate reading, and you won’t over or underinflate the tyres. 

Should you check the spare wheel? 

Yes! Regularly check the spare tyre’s pressure.  

No one wants to use the spare wheel, but you will have to rely on it in an emergency. Regularly checking it’s pressure will ensure you’re safe if you encounter a flat tyre. 

What should your tyre pressure be? 

Most cars have a recommended PSI between 31 and 35. 

BUT the pressure you’ll need depends on the vehicle and the tyre. Often, a sticker is on the inside of your door or under the petrol cap to show this. If not, consult your owner’s handbook or use an online tool.  

If you’re planning to carry additional weight, such as a heavy rooftop box, the pressure requirement may differ, so consult your handbook.  

Need to convert? 1 Bar = 14.5 PSI 

Why is it important to know your tyre pressure? 

To keep you safe and reduce fuel costs! 

Tyres naturally lose pressure over time. Deflated tyres can affect your vehicle’s handling, the comfort of your drive, and your ability to brake. They can also cost you much more fuel, as increased friction means the engine must work much harder.  

How do you inflate your tyres? 

You can inflate your tyres using a tyre inflation kit or a tyre inflation pump at a petrol station. 

Follow these steps to inflate your tyres using a petrol station pump: 

1. Find your recommended tyre pressure. This will be on the vehicle user guide, a sticker on the driver’s door pillar, or the back of the fuel cap.  
2. Check the tyre pressure. Before filling, double-check the current pressure by inserting the tyre inflation nozzle into the valve. 
3. Adjust your tyre pressure as needed. Use the tyre readings to decide whether to fill or release any pressure. 

Note that the tyre pressures at the front and rear will likely be different. Check all four tyres individually. 

Underinflated tyres

Underinflated tyres aren’t good for your car. They increase fuel consumption, wear out faster and irregularly, increase CO2 emissions, and are more hazardous. An underinflated tyre is more likely to burst at a high speed. 

Signs of underinflated tyres: 

• Excessive wear on the inside and outside of the tread 
• Increased rolling resistance 
• Fewer miles to the gallon 
• Understeering (if the underinflated tyre is at the front of the vehicle) 
• Oversteering (if the underinflated tyre is at the rear of the vehicle)

Overinflated tyres 

Overinflated tyres can also be a problem. This is because they’re hazardous on wet roads and have a reduced lifetime as the central part of the tread wears faster.  

Signs of overinflated tyres: 

• Premature tyre replacement 
• Less efficient braking distances 
• Heavy wear on the centre of the tyre 

Why do tyres lose pressure? 

Because of temperature changes, small punctures or cuts, or due to a damaged rim. 

Some tyres deflate faster than others for no apparent reason. You may also not notice a damaged, rusty rim or small tyre punctures. This is why it’s critical to check your tyres regularly.  

About slow punctures 

Slow punctures are less noticeable than typical punctures. This means they go unnoticed for long lengths of time. But they will still cause your tyre to lose pressure and become unsafe. 

You can identify a slow puncture by looking for: 

• Debris in the tyre 
• Vibrating steering wheel 
• Pulled steering 
• Worn tyre sidewall 
• Poor handling 
• Clicking sounds 
• Misshapen tyre 

When in doubt, contact an expert for professional advice. 

UK tyre pressure measurements & law 

The UK legal minimum tyre tread limit is 1.6mm. 

This depth must be even across the tyre's width, the central three-quarters, and all around. If your tyres are under or overinflated, they might break this law due to irregular or excessive wear. Another reason to check your tyre pressure frequently! 

Can I check my tyre pressure for free? 

Yes!  

Some petrol stations and tyre shops provide free tyre-checking services. Check beforehand, though. Most petrol stations use a coin-operated pressure pump, so you’ll need some spare change. 

Other tips for proper tyre care 

Taking care of your tyres includes more than knowing their pressure. You should also: 

• Check the tread for wear 
• Examine for cuts or bulges 
• Check cuts out with specialists 
• Replace tyres regularly 

You should also stay up to date with MOTs, as tyres are checked thoroughly within this test. Being proactive is the best way to stay safe! 

The takeaway 

Knowing how to check your tyre pressure is a vital skill. Luckily, it’s pretty easy and only has to be done every month. Bookmark this article so you always have an on-the-go guide for your tyres! 

About Bumper 

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Author - Joseph Law

Joseph has been writing about cars for over seven years and writing for Bumper for over two, blending his passion for automobiles with a talent for storytelling.

Joseph has written about engineering and cars for Autozilla, Komaspec, and several engineering manufacturers. When he's not writing or tinkering with one of his five cars, Joseph dreams of owning an Alfa Romeo 33 Stradale.