What Makes Your Tyres Illegal?

As we all know, our vehicle tyres are the only part that’s always in contact with the road. So for your car to brake, steer, and stay on the road safely, it is important for your tyres to be in good condition and regularly examined. This means that your tyre condition is key to your driving safety.

Before you wonder what makes your tyres illegal, note that the outer surface of any tyre is made of rubber with a tread pattern. Also, the tread grooves creates traction with the road surface which you’re travelling on. This simply means that your car sticks to the road and moves in whatever direction you instruct it to.

Remember that rubbers are not an everlasting material, this means that the tread pattern on your tyres will wear each time you drive. So your vehicle tyres will require to be changed again and again to maintain safe and legal vehicle tyres.

In the UK, there’s a law that ensures your tyres have a minimum tyre tread depth. So what makes your tyres illegal? Continue reading to find out what the law says about tyres and learn how to check your tyres regularly.

What Makes Your Tyres Illegal?

One of the reasons tyres have tread is to disperse water efficiently. This means that the less tread your tyres have, the more likely your car is to skid on wet roads and this will make you lose steering control. A brand new tyre tread is about 8mm. As said before, there’s a law in the UK which ensures your tyres have a minimum tyre tread depth. So what makes your tyres illegal? It is illegal in the UK to run a tyre with a minimum tread depth that is below 1.6mm round the entire outer circumference. But lots of experts believe that the tread of 1.6mm is too shallow and advises using 3mm as the least measure to change tyres.

What Makes Your Tyres Illegal Theory Test?

what makes your tyres illegal

Indeed, your vehicle tyres may be of different treads and makes. Your tyres might even be second-hand, but they should be in good condition. Tyres should be intact, without cuts or tears. What makes your tyres illegal theory test include:

  • Second-handed tyres
  • Tyres with a large, deep cut in the side wall
  • Tyres of different makes
  • Tyres that have different tread patterns

When Are Tyres Illegal?

When you check some pictures of illegal tyres, you will understand when tyres are illegal. Remember that the legal minimum tyre tread is about 1.6 mm. So tyre tread that is below this measurement is illegal especially in the UK. This is because any tyre that is below this measurement won’t provide you with enough traction on the road while driving. You should make sure you check your tyre tread depth regularly once they get down to 3mm. Try to change your tyres before the tread wears below 2mm.

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Are Perished Tyres Illegal?

Make sure you don’t drive with perished tyres. Perished tyres are illegal. This is because the tyre’s strength and rigidity has already been compromised and there’s a possibility that you will experience a blowout while you drive your vehicle. So whenever you notice a crack around your tyres, make sure you take your car to a garage and have new ones fitted.

What’s The Legal Minimum Depth Of Tread For Car Tyres?

The minimum tyre tread depth is 1.6mm. This means that it is illegal to drive with a tyre that is below this measurement round the entire outer circumference. However, tyre producers built a number of tread wear indicator bars in your car tyre tread area that becomes very visible at 1.6mm. With it, you will know when to change your tyres.

What Causes Tyre Wear On Both Edges?

As you know, tyres will begin to wear out over time. Though there are some causes that make tyres to wear on both edges which are what makes your tyres illegal. They include:

 Alignment: Your vehicle tyres will wear faster and unevenly when you have wrong wheel alignment.

Position: Any tyre on a driven wheel will wear faster.

Load: When there’s excessive load, it increases wear, even vehicle weight. This means that tyres on heavier vehicles will wear faster.

Speed: Note that high speed driving will increase temperature and wear.

Pressure: An under inflated tyre can both increase wear.

Your driving style: Note that aggressive cornering and braking will increase wear.

What Would Make A Motorcycle Tyre Illegal?

Tyre treads are made to provide good wet grip, but you should know that the road surface also has its own significant role to play in tyre to road adhesion. However, wet grip will reduce as tyre tread patterns wear down and as the depth of surface water increases.

But the law in the UK demands that a minimum tread depth of 1mm across ¾ of tyre tread pattern of motorcycle with visible tread on the remaining ¼ for bikes over 50cc. When it is under 50cc needs all the grooves of the original tread pattern to be clearly visible. So if any grooves have worn smooth, then your tyre needs replacement. 

Tyre Cord Exposed

Tyre users and experts advise that tyres with exposed cords might still allow you to drive for approximately 90 to 100 miles when at a reduced speed. But this may be a serious indication of danger. It means that your tyre can blow up anytime, meaning that it is risky to drive with this tyre.


It will be good that you understand the basic UK tyre law on what makes your tyres illegal. But if you’re unsure, you can visit any tyre fitting centre close to you that will be able to advise you on the legality of your vehicle tyres and the tyres you want to be fitted for you.

Note that tyres are the only part of your vehicle that is in contact with the road surface, and this means that your tyres need to be taken care of regularly. Remember that there’s a fine of up to £2,500 for each illegal tyres you use, and this means that if each tyre is below the legal limit, then you might end up paying a fine of up to £10,000.

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