Car tyres – everything you need to know

They’re the unsung heroes keeping you safe on the road; regardless of what car you own, having the right rubber in good condition is one of the most important things to keep yourself and others safe when driving.

We’ll talk you through tread depth, the importance of tyre pressures, how the age of your car tyre can affect performance and what to look for when replacing car tyres. We’ll also think about the best tyres for electric cars, as well as how to ensure your tyres (for any car!) are in tip-top condition.

Summary

We’ll cover:

• Tread depth
• Tyre pressure
• How age affects a tyre
• Replacing car tyres
• and how to look after tyres.

What’s the legal minimum depth of tread for car tyres?

The legal minimum tyre tread depth for a car in the UK is 1.6mm. If you’re stopped by the police and found to have tyres under the legal 1.6mm limit, you could receive a £2,500 fine and 3 points on your driving licence – it’s that serious.

Tyres are your cars only contact with the road beneath. If they’re not up to scratch, you could seriously injure yourself or those around you if your car loses grip. Of course, how you drive and maintain the other parts of your car are crucial too, but tyres often get overlooked because they’re not something we often check regularly… which we should be.

How to check tyre tread depth

Checking your cars tyre tread depth is simple. Of course, your garage or service centre should be keeping you informed of when your car tyres are nearing the legal limit, but they may only see your car once a year. If you do a lot of miles, it’s a good idea to check your tyre tread depths at least once per quarter.

Here’s how:

• You can order a tyre tread depth gauge (these can either be digital or analogue); a small device that will measure the tread depth on your tyre with good accuracy. These can range from £5-£50 depending on how fancy you’re feeling – but even the more affordable ones can give you a decent indication on the state of your tyres.
• You could use a 20p piece; the outer rim of a 20p piece is approximately 3mm wide – if you insert that rim into one of your car tyres grooves, and the rim on the coin is obscured, then you know your tyres are comfortably within the legal limit. If you put the coin in and can see the rim, then you know it’s nearly time to get them replaced.

The fact of the matter is, having a car tyre even close to the legal limit can be dangerous and you should consider the age and general condition of your tyre too when deciding whether to replace them or not. Generally speaking, garages recommend considering changing your tyres when they reach below 2.5mm (especially if they’re aging).

Car tyre pressure

Here’s something obvious: tyres are full of air which, you guessed it, can escape. If too much air escapes, the tyres won’t work optimally, and it can be dangerous. Under-inflated tyres can cause more oversteer (when the rear of the car loses grip and starts to drift) or understeer (where the front loses grip) meaning it’ll be easier for you to lose control of your vehicle in poor weather conditions. It can also increase braking distances and the risk of aquaplaning too.

Plus, under-inflated tyres can increase energy/fuel consumption by a lot more than you might think. If tyres are under-inflated, it means more of the surface area of the tyre is rubbing against the road than is required; more rolling resistance is created and therefore, your car needs to use more energy to move increase fuel costs.

For electric cars, under-inflated tyres could reduce your range and increase your cars energy usage significantly, so keep on top of them!

Increased pressure can also raise the chances of you damaging a tyre long-term sooner than normal, meaning you may need to replace it earlier than expected. According to Halfords, a tyre that is under-inflated by 20% consistently could reduce its lifespan by 20%.

So we know it’s a faff sometimes, but your driving instructor was right all along; it really is important to keep on top of your car tyre pressures.

When should I check my car tyre pressures?

You should be checking tyre pressures:

• At least once a month
• And before any long or ladened journey.

Even with brand new tyres, air will escape slowly through the walls of the tyre, so it’s good check them regularly.

Checking tyre pressures before a long journey is a good idea too, as consistent stress on a tyre can increase the chances of it failing – so do your bit and help it out by ensuring it’s good to go before you set off on that cross-continent trek.

What’s the best tyre pressure for my car?

Wouldn’t it be great if it was a one-size-fits all situation? Sadly, it’s not and it completely depends on your car and the size of the wheels fitted. Handily, there are lots of easy ways you can check which pressure your tyres should be.

Firstly, you could check the pressures online using a tyre pressure tool (like this one available from Kwik Fit – which will also tell you the size of the tyres on your car). Be aware though, different alloys and wheel sizes could have been available when your car was new, so this may not always be 100% accurate and you should check another way to be sure.

Secondly, you can check your vehicle manufacturers handbook or start guide. They sometimes keep the tyre pressure details in there.

Thirdly, you could try inside the driver/passenger door of your car and look for a sticker or stamp on the sill of the bodywork. Manufacturers often give you tyre pressure details there or on a sticker inside the fuel filler cap.

And finally make sure the pressure is appropriate for the type of journey you’re doing. If you’re likely to have the car fully laden with people and luggage, it’s recommended to inflate the tyres higher than usual to make sure the correct amount of the tyres contact area is riding the road. If your car is full and you over-inflate a tyre, it could be dangerous, but under-inflate it and you’ll increase rolling resistance meaning higher fuel consumption and risk of skidding.

Tyre pressure monitoring system (TMPS)

Some cars are also fitted with a tyre pressure monitoring system. This is in-built to your car and is designed to warn you when your tyres are below 80% of their recommended pressure.

The warning could either display on your car as a little symbol or message in the instrumental cluster, or (if your car has an advanced system) it may tell you the exact pressures of your tyres in real time.

In either case, if the warning goes off, you should reinflate your tyres to their recommended pressure as soon as you can and you should never totally rely on the system – it’s still your responsibility to check your tyre pressures at least monthly.

If you notice a strange sensation through the steering wheel while driving after the warning is triggered, it’s possible you have a puncture – in which case you should pull over somewhere safe as soon as possible and change the tyre.

How to check car tyre pressure

If, however, your car isn’t fitted with a TMPS, how do you check it?

You can order digital tyre pressure devices which, when connected to your tyre, will give you a read-out of the tyres pressure and can range anywhere between £5-£35. It’s a good idea to get a solid, reliable device to make sure you’re getting accurate readings.

Alternatively, most petrol stations in the UK have a tyre pressure station you can use to check and inflate/deflate your tyres (though they’ll likely charge you a small fee!).

How to check the age of a car tyre

Knowing how old your car tyres are is important because the older a tyre, the more susceptible it is to failure, even if the tread depth appears well within the legal minimum. Older tyres are more likely to fail or get punctures.

Each car tyre will have a four-digit code on the wall of the tyre within a circular line, like this:

In this case, the number shown is 4921.

The first two digits are the week of the year in which that tyre was manufactured, with the second two digits being the year.

So, in this example, the tyre was made in the 49th week of the 21st year (2021).

Replacing car tyres

The time has come. They’ve served their purpose admirably and kept you safe – it’s time for pastures new. Now what? What do you need to do to replace tyres on your car? Here are a few things to consider:

What tyre size is right for my car?

Ordering the wrong size of something is annoying, isn’t it! But unlike clothes, tyres aren’t as easy to return and there’s definitely no “Oh well, it might fit if we squeeze…”.

So, you should be confident you know the size of the tyres on your car before you go purchasing new ones.

Tyre sizes are laid out like this: 123/12 A12 – an example would be P205/65 R16.

• The first number, 205, is the width of the tyre in millimetres.
• The second number, 65, is the height of the tyre as a percentage of the full width.
• The letter shown is the type of tyre (don’t worry too much about this).
• And the final number is the wheel rim diameter in inches – i.e., this tyre will fit a car with 16” rims.

What tyres are on my car?

To check the size of the tyres on your car, you should:

• Check your vehicle handbook – it may say in there for you
• Check the inside of the driver/passenger door or fuel filler cap for a sticker with the information
• Check online using a tyre tool like Kwik Fit – this will use your car’s registration to find the right tyres, but don’t always use it as gospel if you’re not certain
• Or check the existing tyres on your car – the tyre will have the XXX/XX XXX written on the wall of the tyre.

The manufacturer of the tyre, such as Michelin or Dunlop for example, will be written on the side – should you want to choose the same tyres again.

What are the best tyres for my car?

That depends on your priorities, really!

All tyres are subjected to the same rigorous safety tests, so that shouldn’t be a concern to you. Though, some tyres may offer better grip than others.

Tyres are usually split into three types: budget, mid-range and premium. Budget tyres are (fairly obviously) more affordable with premium tyres costing the most and mid-range bridging the gap. But what’s best for you?

Well, tyres generate noise, so if you find tyre roar frustrating you may be better off getting a more premium tyre. Fuel economy is important too, with more expensive tyres offering better rolling resistance meaning fewer trips to the pumps or chargers. Grip and wet weather performance is a factor as well – though all tyres will have met the standards required, if you have a faster car (or a quick accelerating EV) you may be better off getting a premium tyre to reduce the chances of unwanted wheelspin or skids – especially in rainy weather.

Then there are seasonal tyres which you can get specifically for Winter or Summer. Winter tyres offer better performance in colder weathers, particularly if you live in an icy or snowy area.

Specialist tyres are an alternative if you regularly go off-roading for example or own a campervan or sports car.

And finally, EV tyres are those designed specifically for electric vehicles to be as environmentally friendly as possible while maintaining the best efficiency and grip for your EV. They’ll help you get the best range out of your EV and are designed to combat the higher degradation caused by a heavy battery pack – and, because electric cars are silent, they’re usually quieter too. Yes, you can fit ordinary car tyres to an electric car but Kwik Fit say you could reduce the range by around 20%!

Should I change tyres in pairs?

Where you can, yes. Changing just one side at a time can cause uneven rolling resistance on the same axle, meaning you’re more likely to lose grip in some situations. You should always change tyres in pairs if you can.

How to look after car tyres

At the end of the day, the condition of your cars tyres is heavily dependent on the surfaces they’re driving over, but you can do your bit to look after them:

• Avoid harsh acceleration and braking – it seems obviously really, but squealing rubber at the lights every time you pull away won’t preserve your tyres (or your car as a whole for that matter!). Where you can, be as smooth as possible – and that includes while braking too. The regenerative braking on an electric car can help here.
• Corner smoothly – If you’re clinging on for dear life inside the car, think how your tyres feel! Take corners smoothy and steer progressively to keep your tyres in top condition.
• Try to avoid potholes and rough road surfaces – quite an obvious one; the smoother the road surface, the longer life your tyres will have. It’s not that easy or simple though and you shouldn’t be swerving all over the road just to avoid potholes if it’s not safe.

There you have it – all you need to help you keep on top of your car tyres.

And the best bit? If you’re subscribed to elmo, tyres* are included as part of your subscription.

*We’ll replace the tyres on your elmo car when they get around the legal minimum – punctures are not included.

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