Help and advice

Car Maintenance

How to Keep Your Tyres in a Roadworthy Condition

tyre tred

We should take care of the tyres on our cars as our lives depend on them.  Worn, over-inflated or under-inflated tyres can be dangerous and lead to accidents. 

Green Flag say that 40% of all their call-outs are related to tyres

Why it’s important to check tyre tread?

Checking your tyre tread depth is one of the most important checks you can make on your car.  Having the correct tread enables your tyres to grip the road. Without tread the tyre’s ability to grip a wet road is severely limited, making it almost impossible to stop, turn, accelerate and corner.

Aside from the safety issues, you can be fined up to £2,500 and get 3 penalty points for each worn tyre.  If all four tyres are illegal that’s £10,000 fine and you could lose your licence.

What is the legal depth for your tyres?

The minimum depth of tread on your tyres is 1.6 millimetres, across the central ¾ which is 75% of the tread around the complete circumference of the tyre.

What is the expert-recommended minimum tyre tread depth?

Manufacturers and safety experts believe the 1.6mm legal minimum is insufficient to guarantee safety. Therefore most recommend a minimum tread depth of 3mm.

There is a significant difference in wet braking distance between a tyre worn to 3mm and one worn to 1.6mm which can be as much as 44%. 


When should I replace my tyres?

If your tread depth is between 1.6 and 3mm then it is time to start thinking about ordering a new set of wheels for your ride!

The Royal Society for the Prevention of Accidents (RoSPA) recommends that tyres should be replaced as soon as the tread reaches 3mm.

How do I check my tyre tread depth?

There are a few different ways you can check the tyre tread depth:

Tread Wear Indicators

Tread wear indicator bars are moulded into the tread grooves of tyres at regular intervals. They are small blocks of rubber that help you see with a quick visual check if your tyres need replacing. If the tyre is flush with these, it is below the legal limit and needs replacing.

Depth Measuring Gauge

A tyre depth measuring gauge is a purpose made tool that quickly measure the depth of an individual tyre groove. It’s small enough to keep handy in your glove box for regular checking.

20p Test

A 20p coin has a border which measures 3mm. Insert a 20p coin into the lowest tread depth of your tyres. If you can’t see the outer rim around the edge of the coin, then your tyre is safe. If you can see the rim then your tyre tread is less than 3mm and should be replaced. 

Why should I regularly check tyre pressure?

Tyres should be correctly inflated according to your vehicle’s handbook.
As well as affecting your car’s handling and braking performance, over-inflated or under-inflated tyres will reduce their lifespan. Under-inflated tyres will also reduce the fuel efficiency of your car.

A correctly inflated tyre should wear evenly across the tread, but one that’s incorrectly inflated will wear more quickly and unevenly.

An under-inflated tyre will wear more heavily on the outer shoulders, while an over-inflated one will wear more in the centre of the tread.


What is the correct tyre pressure?

The recommended inflation pressure is shown on a placard attached to the body – usually on the driver’s door pillar – and also in the owner’s manual.

Inflation pressures are given for normal driving, and also when loaded up with the maximum number people the car can legally carry and luggage.

So remember that the pressure will need to be increased when the car’s fully laden, such as heading off on holiday with a car full of children, and luggage.

How to check tyre pressure?

Tyre pressures are always quoted for cold tyres, so check them before starting out on a journey, not afterwards. 

Tyre pressure increases when the car is driven, so checking it when tyres are warm will give you an incorrect pressure reading.

It’s wise to also check for any bulges, cuts or debris embedded in the rubber that will impact the safety and performance of the tyre. If you have any doubts get it checked by a professional tyre fitter.

How often do I need to check my tyres?

Ideally you should check your tyre tread depth and pressure at least once every two weeks, and at a minimum once a month.


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