When to Change Your Car Tyres: A UK Guide

Summary

• Change tyres at 3mm tread depth for optimal wet weather safety, although the legal minimum in the UK is 1.6mm.
• Replace all tyres, including the spare, once they are 10 years old, as rubber degrades over time regardless of tread.
• Regularly inspect tyres for signs of damage such as bulges, cuts, cracks, or uneven wear, which indicate immediate replacement is needed.

Of all the bits and pieces that make up your car, only four of them are supposed to touch the road. They’re your tyres, and they have the ridiculously important job of keeping a tonne or two of metal, plastic, and people pointing in the right direction.

Yet, most of us don’t think about them until we get a flat, a scary skid in the rain, or an MOT advisory note.

So, let's talk about it. When should you actually change your tyres? The answer isn't just one thing; it's a mix of legal rules, common sense, and listening to what your car is telling you.

The Big One: Tyre Tread

Think of the tread on your tyres like the grip on the bottom of your favourite trainers. When they're new, you feel planted and secure. When they’re worn smooth, you wouldn't dream of running on a wet floor. It’s the same principle, but with much higher stakes.

The Law vs. Reality

In the UK, the law is pretty straightforward: your tyres must have a minimum tread depth of 1.6mm. This isn't just a suggestion; it’s a hard rule. The tread needs to cover the central three-quarters of the tyre, all the way around.

Get caught with less, and you’re looking at a fine of up to £2,500 and three penalty points... per tyre. Yep, if all four are illegal, that’s a potential £10,000 fine and enough points to lose your licence.

But here’s the thing: 1.6mm is the legal minimum, not the safe minimum. It's the point where the government says "Okay, this is officially dangerous." Performance, especially in the wet, starts to fall off a cliff long before you get there.

Most safety experts, recovery services, and tyre fitters will tell you to think about changing your tyres at 3mm.

Why? At 50mph in wet weather, a car with 1.6mm of tread can take an extra 8 metres (that’s two whole car lengths!) to stop compared to one with 3mm of tread. That’s the difference between a near-miss and a nasty accident.

How to Check Your Tread (It's easier than you think)

You don’t need any fancy tools. All you need is a 20p coin.

• The 20p Test: Take a 20p coin and pop it into the main grooves of your tyre. If you can't see the outer band of the coin, your tread is likely 3mm or more. You're in the clear. If you can see that outer band, your tread is getting low, and it’s time to get them checked professionally.
• Tread Wear Indicators: Your tyres have their own built-in warning system. Look inside the main grooves, and you’ll see little bars of rubber, about 5mm wide, running across them. When the rest of your tread wears down to become level with these little bars, you’re at or very near the 1.6mm legal limit. It’s an immediate signal to get them replaced.

The Silent Killer: Tyre Age

"But they look fine! There's loads of tread left!"

This is a common trap, especially for cars that don't cover many miles. Rubber, just like any other natural material, degrades over time. It dries out, gets brittle, and loses its flexibility. Think of an old rubber band you find in a drawer – it looks okay, but snaps the second you try to stretch it.

Your tyres are exposed to sunlight, temperature changes, and oxygen, all of which accelerate this ageing process.

So, is there a legal age limit?

This gets a bit confusing. For regular cars, there is no legal age limit in the UK. However, for buses, coaches, and HGVs, it became illegal in 2021 to use tyres over 10 years old on the front axles.

What does that tell you? It tells you that the experts know old tyres are a risk.

As a rule of thumb for your car:

• After 5-6 years: Get your tyres professionally inspected at least once a year.
• At 10 years: Replace them. No excuses. It doesn't matter how much tread is left or if they belong to the spare you've never used.

How to find your tyre's "birth date"

It’s surprisingly easy. Look on the sidewall for a series of characters that starts with "DOT". At the end of that line, you'll find a four-digit number.

• The first two digits are the week it was made (01-52).
• The last two digits are the year.

So, a code of 4718 means the tyre was made in the 47th week of 2018. If you see a three-digit code, the tyre was made before 2000 and should have been replaced a long, long time ago!

Damage and Wear: The Telltale Signs

Sometimes, a tyre will tell you it's had enough long before its tread wears down or it gets too old. A quick visual check once a month (and especially before a long journey) can save you a world of hassle.

Here’s what to look for:

• Bulges, Lumps, or Blisters: If you see a bubble on the sidewall, stop driving immediately. This is a sign of internal structural damage, often from hitting a pothole or kerb. Think of it as a hernia for your tyre – it's a weak spot that’s ready to blow.
• Cracks and Crazing: A web of fine cracks in the sidewall rubber is a sign of "dry rot." The rubber is getting old and brittle.
• Cuts, Tears, or Exposed Cords: Any cut deep enough to see the fabric or metal cords underneath means the tyre is toast. It's illegal and incredibly dangerous.
• Uneven Wear: Are your tyres wearing down more on one edge than the other? Or just in the middle? This isn't just a sign to change your tyres; it’s a symptom of another problem, likely with your wheel alignment or tyre pressure. Getting the underlying issue fixed is crucial, otherwise, you'll just ruin your new set of tyres.

What About the Seasons?

"Do I really need winter tyres in the UK?" It's a fair question. Our winters can be anything from mild and wet to a full-on blizzard.

The key isn't snow; it's temperature.

The 7°C Rule:

Think of it like this. The rubber compound in a "summer" tyre (the standard type fitted to most cars) is designed for mild-to-hot weather. When the temperature consistently drops below 7°C, that rubber starts to harden, a bit like plastic. It loses its grip.

Winter tyres use a softer compound with more natural rubber, which stays flexible and grippy in the cold. This gives you better traction and dramatically shorter stopping distances on cold, wet, icy, or snowy roads.

All-Season Tyres: The British Compromise?

For many UK drivers, all-season tyres are the perfect middle ground. They offer much better cold-weather performance than a summer tyre, but without the hassle of swapping and storing two full sets. They're a jack-of-all-trades, master of none, but for the UK's changeable climate, that’s often exactly what you need.

You can fit all-season tyres at any time of year, but the logical time is when your current set is due for a change anyway.

Your Questions Answered

Can I just replace one tyre?

You can, but it's not ideal. You should always replace tyres in pairs (both fronts or both rears) to keep the handling balanced. If you only replace one, your car might pull to one side when braking.

If I'm replacing two, should the new ones go on the front or back?

This one surprises people: the new tyres should always go on the rear axle. Even on a front-wheel-drive car. The rear tyres provide stability, and having the best grip at the back reduces the risk of the car spinning out, especially in the wet.

My MOT is due soon. Will my tyres pass?

The MOT tester will check for the 1.6mm legal minimum, and they'll also look for any of that nasty damage like bulges or exposed cords. You can fail an MOT for having the wrong size or type of tyre fitted, too. A quick 20p test before you go can save you the stress of a fail.

What about the spare?

Don't forget it! The age rule is just as important for the spare. There’s no point having a spare tyre that’s 12 years old and ready to disintegrate the moment you need it most. Check its pressure and condition as part of your regular vehicle safety checks.

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Ultimately, knowing when to change your tyres comes down to paying a little bit of attention. They're constantly talking to you through the way your car feels, sounds, and looks. Don't wait for a dangerous skid or a failed MOT to listen.

Go on, grab a 20p coin. It’ll take two minutes.

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