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How Do I Know If My Tyres Need Changing

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  • 23-08-2022
How Do I Know If My Tyres Need Changing

This article discusses how to know if your tyres need changing? When should you replace the tyres on your car?

When should you replace the tyres on your car? 

Tyres are the one area of a car that most motorists overlook in terms of condition and maintenance. This is probably why more than 10% of cars fail their MOTs thanks to worn-out or defective tyres. 

And, funnily enough, they're one of the easiest parts of your car to look after. It's easy to stay on top of your tyre maintenance with basic checks and a little know-how. 

Warning signs that your car's tyres need replacing

A few key factors affect how your tyres degrade, including road conditions, weather conditions, and driving style. 

Whether it's potholes and poorly looked-after roads or loose stones, the roads you drive on constantly attack your tyres causing them to wear and ultimately lose their grip. Therefore, it's important to look for the tell-tale signs that your tyres might need replacing.


One clear sign that you need to replace your car tyres is when their tread becomes too low. Just like your old pair of trainers, you're more likely to slip in wet conditions when the tread goes.

It's one of those facts we pick up when we're learning to drive but instantly forget once we've passed, but the legal tread depth for all vehicles in the UK is 1.6mm along the tyre's circumference.

Thankfully, most tyre manufacturers provide an indentation or tread bar that runs across the central three-quarters of its tread that shows when it is too worn.

It's natural to feel some vibration while driving your car along the road, especially if those roads are particularly rough. However, if you notice the same amount of vibration and rattling as you drive along fresh and smoothly laid motorways, there's clearly an issue. While this is also a sign of faulty shock absorbers or poor wheel alignment, it's also an indicator of worn-out tyres.

If your vibrating isn't caused by any of the above issues, there's likely something wrong with your car tyres themselves. But this will only lead to tread wear in the end anyway.

Therefore, if you notice any undue vibrations, always get your tyres checked. A professional mechanic at your local tyre garage will know what to look for when you mention strange vibrations, and if it is your tyres, they can replace them for you there and then.

Even if you have top-of-the-range tyres on your car, you're likely to notice cracks in the sidewall at some point. This is due to the chemicals and oils in the rubber compounds that break down under UV light over time. Cracks should never be ignored, as they can lead to the tread separating from the tyres or even a sudden blowout, which is significantly dangerous.

Therefore, as soon as you notice a crack or blister on one of your tyres, you should have them replaced. Thankfully, these cracks usually appear in the sidewall, which is the easiest part of the tyre for you to inspect visually.

Most drivers will be familiar with how their tyres usually sound as they purr along the roads. Therefore, it's time to check your tyres when you notice strange noises or something out of the ordinary. When there is a crack in your tyre sidewall, a flat tyre or a puncture, you'll notice a squeaking or whining noise as the air compression in the tyre.

Of course, strange noises aren't just a sign of a defective tyre; there could be other issues with the car. So, if you notice any strange noises in your car, always have it investigated by professional tyre experts. 

Like all the components of your car, your tyres have a lifespan. If you buy brand new tyres, this lifespan will typically be five years. This is when the compounds in the rubber begin to break down and break apart, leading to cracks and blisters.

Of course, most tyres wear out before five years, given the wear and tear they're usually subjected to, so if your tyres make it to this time, it's a good idea to replace them to ensure your grip levels remain safe. 

Tyre tread depth and tyre safety

Checking your tyre tread depth is one of the most important checks you can carry out on your car. If your tyre tread is worn down, the contact patch between you and the road is reduced, making it far more dangerous to drive. It's also a legal requirement to have a safe tread on your tyres. If you don't, you risk not only endangering yourself and other motorists, but you could face a £2,500 fine per worn tyre and twelve points on your licence.

What is the legal tyre tread depth?

Again, the legal tyre tread depth in the UK is 1.6mm across the middle 3/4 of the tyre. This must be the case around the entire circumference of the tyre. 

How to check your car tyre tread

There is one easy method for any motorist to check that their car tyres have the required minimum tread depth of at least 1.6mm around the entire circumference. This method is the 20p test.

20p Test

This is the simplest way for you to check the tread depth on your car tyres. All you do is take a 20p coin and slot it into the tread grooves.

At this point, if you can see the coin's outer band above the tread, your tyre tread is below the legal limit and should be inspected or replaced by a professional.

If the tread covers the outer band of the 20p coin, your tyres are safe and legal to drive on. 

If you take frequent long journeys in your car, then you should conduct the 20p test every couple of weeks.


Again, you can always refer to the tyre tread wear indicators that are embossed into the sidewall or tread of most modern tyres to tell if they are too worn. Once your tread becomes flush with these tread depth indicators or indentations, then they are too flat and must be replaced. They can also tell you if you have uneven tyre wear or irregular tread wear. 

What happens if you have an accident on illegal/bald tyres?

Driving on tyres with a low tread, or worse if they are completely bald, is incredibly dangerous for you, your passengers and other road users. If you cause or are involved in an accident with illegal tyres, there are some serious consequences coming your way. Any insurance claim you make will be invalidated, meaning you will have to pay for any repairs for your car yourself. 

Again, you also run the risk of facing serious fines if you are caught driving on defective tyres. You'll be given up to twelve penalty points on your driver's licence and could face £2,500 fines for each of your worn tyres. Working that out, if all four of your tyres fail inspection, you could end up paying £10,000. To avoid this, you can invest in proper tyre tread depth gauges or other equipment to help you keep on top of your tyre tread levels. These will tell you when a tyre replacement is required. 

If you require annual servicing, choose a garage that you can trust. Follow the link below to contact a car service mechanic in Watford.