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Driver Safety: Why Tyre Tread Depths Are Important

6th August 2018

Understanding the importance of tyre tread depth, and how to check yours, will help keep you safer

Tyre Tread Depth

Take a look at these numbers. In 2016 there were 37.1 million vehicles licensed for use on UK roads, with 1.87 billion car miles driven. During this period there were just under 180,000 road casualties, and of these 1,792 were fatalities – representing the highest level since 2011. Not good.

We know from our experience of championing UK drivers and road safety that it can be difficult to comprehend such large figures, so consider this small number instead: 1.6 mm. This represents the minimum tread depth that your tyres must have to be road legal in Britain. It doesn’t sound a lot, does it, but it’s legally the difference between having tyre grip, or becoming one those road casualties.

Tyre Tread Depth Contact Patch

Sound dramatic? Believe us, it isn’t. When you realise that the amount of a tyre that is in contact with the road at any given moment in time is roughly the size of a smartphone, you better understand just how important your tyres are – and the tread they do or don’t have.

With this very limited contact patch, your tyres need to be able to remove enough water quickly enough to ensure grip is maintained with the road. And to achieve this, your tyres require adequate tread depth. Alas, despite numerous safety campaigns by the tyre industry, many drivers still don’t realise this, and, as a result, have allowed their tyres to wear down to the point where they’re endangering their driver safety.

Stopping Distances

Tread depth effects your breaking distances and chances of aquaplaning

While is 1.6 mm is the UK legal minimum tyre tread depth, many road safety organisations, and tyre experts, like Merityre, and premium tyre manufacturer, Continental, recommend that your tyres have a minimum tyre tread depth of 3 mm. Why? Because – over many years – independent braking distance tests have conclusively revealed that in wet weather conditions – something we get a lot of in the UK – the difference in stopping distance for tyres with 1.6 mm and 3 mm of tread depth is almost twice as far to come to a full stop.

Our graphic, above, demonstrates the difference in stopping distances for vehicles fitted with summer tyres on a wet road. Even at relatively modest speeds (21 mph residual speed for the 3 mm tread, and 27 mph residual speed for the 1.6 mm tread) the difference is worrying.

In a built up, town centre or residential setting – such as a side street where school children are distracted while crossing the road – the consequences of taking longer to come to a safe, full stop are potentially catastrophic. And as for travelling at high speed on a motorway in wet conditions, as so many motorists do…

And then there’s the threat of aquaplaning – when your tyres completely lose contact with the road, and as a result travel on top of the water. Tyres are resistant to your attempts to accelerate, brake or steer, leaving you out of control. Fortunately – in the vast majority of cases – drivers manage to regain control, but it’s not always the case. Good tread depth helps to reduce the threat of aquaplaning.

Aquaplaning

Your tyre tread wear is determined by how you drive

When a high quality, premium tyre leaves the factory – for instance, the award winning ContiPremiumContact™ 5 – it features a full 8 mm of tread depth. Because of this, the tyre can disperse large amounts of water very quickly and efficiently from the road surface. This improves your grip, the vehicle’s handling, and – ultimately – your driver safety. But not all tyres are the same…

A tyre’s compound, in combination with how a car is driven, will determine your tyre wear. if you’re doing hundreds of miles each month at 70 mph on motorways, they’ll deteriorate faster than say, for example, someone doing the daily school run at 30 mph or less. But in an exact like for like usage comparison, the superior compounds used for premium tyres will wear down slower than for cheaper, budget tyres.

20p Test

Checking tyre tread depth is easy – here’s how

Purchasing a tyre tread depth gauge is simple enough, especially in this age of online shopping, but an alternative is the “20p Test”. It’s an extremely handy way to check your tread, without the need for a gauge. To do so, all you have to do is place a 20p coin into the tread grooves that run along the length of your tyre. Do this at various points, so as to get a breadth of results.

If the coin’s outer band is obscured, you know your tread is above the legal minimum. But if at any point you can still see the top of the band, your tyres may be illegal. You could be breaking the law, as well as endangering your driver safety. You should seek immediate expert advice from your local Merityre professionals, and if necessary have your tyres changed.

If you choose not to, and are stopped by the police with illegal tyres fitted, you risk incurring a fine of £2,500, and three penalty points for EACH illegal tyre. Ouch. It really isn’t worth it, is it?

Need expert advice on tyre tread depths? Speak to Merityre now

We cannot emphasise enough just how important your tyre tread depths are, so if you’re in the least bit unsure about yours, talk to your local Merityre professionals for impartial, expert tyre advice, as well as the best fitting solutions for your vehicle.

Find your nearest location here.