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Knowing how to reduce your stopping distances in wet conditions could save your life

12
Sep

If you’re struggling to recall, it’s worth recapping just how vital they are, and how the tyres that you choose to fit to your vehicle – as well as the prevailing weather and temperature of the time – will influence the length of this distance. Stopping distances were important then, and they’re just as important now.

What exactly is a ‘stopping distance’?

Some drivers mistakenly think that it is simply the distance a vehicle travels from the moment the brakes are applied, to when it comes to a stop. This is not the case. In fact, this description only actually covers ‘braking distance’, it’s a large and vital component of stopping distance, but it’s not the only one. Before this value can even be considered, there’s an equally important factor – “thinking distance”.

It may only last what can seem a very short time, but thinking distance is the amount of road you have travelled during the time it takes to determine that you actually need to brake – and subsequently react. This seemingly small amount of time can result in your vehicle travelling – in relation to the circumstances of needing to brake – a very long way. This is especially true if you’re travelling at high speed.

To be clear, stopping distance equals thinking distance plus braking distance.

Thinking distance can be influenced by the vehicle’s speed, the driver’s visibility, tiredness and sobriety, as well as any number of internal and external distractions, at the time.

Braking distance is definitely influenced by the vehicle’s speed, the weather, and the tyres fitted –  specifically their condition, type and quality. It goes without saying that travelling at high speed, particularly in poor weather, requires a longer braking distance to come to a full stop, compared to that of slower speeds on a clear, warm day. But what about your tyres? How significant a role do they actually play?
 

Tyres make a difference to stopping distances

In fact your tyres play a massive role in the outcome of your stopping distances – especially when it’s been raining, or snowing. The impact of these conditions on your ability to safely come to a full stop cannot be underestimated. The condition and quality of your tyres can either minimise or increase the length of your stopping distances. The type of tyres you have fitted – in relation to the time of year, and temperature – is also a factor. Let’s look at these in detail.
 

Stopping distances are influenced by the condition of your tyres

The condition of your tyres will significantly influence your ability to brake effectively. Tyre pressures, tyre damage, and tyre tread depth are important factors.

Tread depth helps to determine just how much water can be removed from between your tyres and the surface you’re driving on. A deeper tread depth allows water to be removed quickly and efficiently. Conversely, tyres with low tread depth typically struggle to remove water as effectively.

The rate of removal matters because it dictates how much grip your tyres can achieve. With less grip, it means it will take much further to come to a complete stop safely. The more tread depth your tyres have, the greater the grip – and the shorter your stopping distances will typically be.

In Britain, the legal minimum tread depth is just 1.6 mm, but the vast majority of tyre experts – including Protyre, and leading premium tyre maker, Continental – strongly recommend that your tyres have no less than a minimum of 3 mm of tread depth.

Why? Simply because in our experience, independent braking distance tests conclusively show time and time again that in wet weather conditions, it can take up to two full car lengths further to come to a stop with 1.6 mm of tread, compared to stopping with tyres that have 3 mm of tread.

Two car lengths is a considerable distance, especially at high speed, or in poor visibility, and can certainly be the difference between avoiding a collision, or having one – and not just with another automobile…

You cannot underestimate the importance of having good tyre tread depth – it’s vital in determining your final stopping distance… but it’s not the only factor.

As the weather changes, so too should your tyres

Did you know there are different tyres for different seasons? Not many drivers in the UK do, with the overwhelming majority having ‘summer tyres’ fitted to their vehicles all year round. It’s one reason why, for instance, Continental’s award winningPremiumContact™ 6is a big seller across many vehicle segments. On the continent, it’s a different story, with many of our European cousins switching to ‘winter tyres’ towards the end of each year. But why?

Those UK drivers that are aware of winter tyres often believe the misconception that they’re just for driving in snowy weather conditions, and that – since we don’t get very much snow in Britain – there’s no need to switch to them. While it’s very true that winter tyres far outperform summer tyres in snowy conditions, it’s not the primary reason for fitting them. In fact, the true motivator for switching tyres istemperature.
 

The right tyres for the right climate conditions

You wouldn’t typically wear a pair of fur lined boots in summer, or flip flops in winter, right? Why? Because neither type of footwear is optimised or appropriate for the season. The same principle applies to your tyres.
Winter tyres easily surpass the performance levels of summer tyres when the temperature gets down to 7°C and below. At this temperature range, in a like for like comparison, stopping distances are significantly shorter for vehicles fitted with winter tyres. How much shorter? Again, independent research shows it can be up to two car lengths, and – as already addressed with tyre tread depth – that’s a significant distance.

The reason winter tyres perform so much better at 7°C and below is down to the totally different compounds they’re made from. Summer and winter tyres are made from combinations of materials that are optimised for separate temperatures, with each designed to perform optimally in its appropriate climate.

Because of the way the compound is made, summer tyres become much too hard at 7°C and below, and, as a result, offer much less suppleness and grip than winter tyres – which are specifically designed to thrive at this temperature range.

Conversely, winter tyres – with their much softer compounds – aren’t designed to cope with the warmer temperatures above 7°C. At this range, they become too sticky and sluggish, leading to very poor rolling resistance, and becoming a huge drain on fuel.

And what of all season tyres? Surely – as the name aludes to – they offer the best of both worlds, right? Actually, no. If only it were that straight forward. The very technical process of creating a new tyre involves a delicate balance between attaining performance, safety, comfort, and economy characteristics. Tyre manufacturers put different emphasis on each, depending on the driver segment they’re engineering the tyre for. But there’s only so far manufacturers can go before a bias towards one particular characteristic has a negative impact on the others.

And, ultimately – at its heart – the all season tyre is a compromise on the optimal characteristics of dedicated summer and winter tyres. Yes, some all season tyres offer a good spread of warm and cold temperature qualities, but they can never match the optimal performance levels of their specialist stablemates – and that includes delivering shorter stopping distances in either summer or winter temperatures. That said, Continental’s highly regarded AllSeasonContact™ tyre comes close, offering drivers a great balance of summer and winter driving attributes.

Quality always matters, and makes a difference

On the subject of tyre compounds, whether for summer, winter or all season tyres, at the end of the day – like so much else in life – quality matters. Not all compounds are the same. Some are far and away superior to others, and as a result these tyres typically perform better. The compounds that are used for premium tyres – like those made by Continental – are much better than those found in cheaper, budget tyres. Why? Simple. Tyre manufacturers, like Continental, invest millions and millions every year inresearch and development, the result of which are compounds that deliver noticeably better performance at the temperatures they’re engineered for. Because of this, in exact like for like comparisons,premium tyreswill always deliver superior grip, performance, and safety. It’s one reason why so many of their tyresregularly win independent tests and awards.

Grip – achieved through high quality, seasonal tyres, in good condition – will noticeably reduce your stopping distances.
 

Unsure about stopping distances? Talk to the experts at Protyre

If you’d like to discuss stopping distances with a tyre expert, get in touch with Protyre. Our experienced team of tyre professionals will guide you on how to reduce yours, as well as offer you impartial, expert advice, and the best fitting solution for your vehicle.

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About the author

Article Author Photo
By Gwyn Fennell
Gwyn has been in the motor industry for over 35 years with experience in vehicle design, electrics, engine management, geometry and of course tyres. Continental has been Gwyn’s home for the past 15 years, where he has become a qualified trainer and examiner to both IMI and NTDA standards and now working towards the IQA qualification. Gwyn’s job has evolved and expanded in recent times and a more accurate but less pleasing to read title would be Technical Customer Service & ContiAcademy Training Centre Manager. It’s no surprise that Gwyn has excellent knowledge from the tyres up so when any technical questions come his way you know he’ll be providing the best advice possible.
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