Dunlop SP WinterSport 4D launched

On 14 March Dunlop launched its latest high performance winter tyre – the SP Wintersport 4D – with the frozen lakes of Sweden providing a suitably cold and slippery environment for journalists from across Europe. Following on from the critically acclaimed SP Wintersport 3D, the new cold weather rubber boasts lower fuel consumption (due to 11 per cent better rolling resistance) and greater road handling and safety capabilities than its competitors and predecessor.

The Dunlop SP Wintersport 4D is available in 37 variants covering over 84 per cent of the total European car parc. Sizes range between 195/65 R15 and 255/35 R19. While the tyre is being released across a range of H to V speed ratings, Tyres & Accessories understands that W-rated variants will be made available shortly, making Dunlop's latest cold weather product a true UHP winter tyre. Audi and BMW are among the OE marques already associated with the newly launched product.

According to company representatives, the new tyres will start to filter through the normal distribution channels in the month or so following the launch. The price of the new tyre is expected to vary from size to size and due to the sky-high raw material prices. However, Dunlop reports that the 4D will be priced 3 – 4 per cent higher than its predecessor over and above a 10 per cent price increase caused by the spiralling input costs. This means the same stock keeping unit (SKU) will be 10 per cent more than in 2010 for as long as they are available and the new 4D SKUs will be 13 – 14 per cent more expensive.

Cold weather market heats up

Before anyone points out the fact the land of Elks and Reindeer is home to considerably colder weather than the rest of Western Europe in general and the British Isles in particular, consider this: temperatures fluctuated between -11 and +3 degrees Celcius throughout the event, which is well within the temperature range Britain and the rest of Europe has experienced during the last two winters.

Not only does this make springtime Sweden a good destination for tyre development and product launch activities by providing an at least partly familiar driving context for the widest range of European markets, but it also highlights the fact that Europe is becoming an increasing strong winter market. Between 2008 and 2010 sales of passenger car winter tyres grew by roughly a third (due to the significant market fluctuations caused by the global financial crisis, it is probably not worth directly comparing the last three years with figures from the years before the credit crunch).

According to Europool figures quoted by Dunlop representatives during the course of the Wintersport 4D launch, winter tyres accounted for a quarter of all European tyre sales recorded during 2008. The proportion rose 4 points (13 per cent) to some 29 per cent a year later. By 2010 winter tyre sales accounted for almost a third (32 per cent) of all passenger car tyre sales across Europe.

Those in the know say that this is driven by two key factors – increasing implementation of winter tyre legislation by the various European governments and increasingly erratic winter weather. As if to prove that first point, during the week of the launch the French parliament announced that there are plans underway for a winter tyre law across the channel. Currently 21 countries in Europe have full or partial winter tyre requirements.

However, while legislative changes may account for the increased take-up in already strong winter markets such as Germany (which has been officially ‘encouraging’ the use of cold weather orientated products for some years and officially made winter tyre fitment mandatory in 2010 – up 51 per cent between 2008 and 2010) and Austria (up 25 per cent between 2008 and 2010), it doesn’t for example explain why winter tyre sales shot up 464 per cent over here in blighty.

That’s where the weather comes in, with the Siberian Arctic breeze the UK has experienced over the last two winters appearing to have spoken louder and more immediately than the many pro-winter tyre words uttered in the market over many years. While the Europool figures supplied by Dunlop only include tyre sales of the manufacturers producing tyres within Europe, wholesalers importing non-Europool brands confirm the growth trend, with one large UK business telling T&A that the company sold between three and four times more winter tyres than they had projected last year and could have sold many more had it not been for supply difficulties.

At this point is worth pointing out that the very strong UK winter tyre market growth figures have shot up from a very low base and only now are hovering around the very low single digit percentages of overall UK market share (based on the generally accepted UK total market figure of approximately 31.5 million units a year). However with some sources now suggesting that winter tyres account for around 20 per cent of the similarly temperate Dutch market, strong growth in the mature German market and continuing increased take up in other regions such as the Polish marketplace, the point still stands.

The winter tyre segment is an increasingly high performance marketplace

In addition to the increased take up of winter tyres in general, something else that is noticeable when you look back over the last five or six years of winter tyre sales is that the cold weather market has followed development of the overall tyre parc when it comes to high performance technology. As the popularity of large sizes and high speed ratings have increased throughout the passenger car tyre market, so it seems winter tyres have followed suit.

While the ratio of standard winter tyres to high performance tyres stood at 83:17 in 2005, during the following five years the top end of the segment grew to point that more than a quarter of winter tyre sales could be described as “high performance” in 2010. By this point the ratio stood at 72:28 in what had become (as we have seen) a considerably larger winter tyre segment.

During the same time period, further market research conducted by KANO demonstrated that winter tyre drivers demand a tyre that balances all-round winter performance and the safety of enhanced grip, while at the same time being a product that attains high-level recognition from magazine tests. And it was this sales context and these consumer demands that prompted Dunlop to make the various technological modifications that can be seen on the so-called four dimensional winter tyre.

4D? Four dimensional tyre technology

First off, Dunlop’s decision to include 4D in the name of the tyre set to supersede the SP Wintersport 3D means more than just a generation newer than its predecessor. Rather it refers to the development of the previous generation’s trademark 3D sipe technology. The new tyre may not answer the philosophical and scientific questions of the existence of a fourth dimension in time and space, but it does offer an completely revised siping structure designed to operate in four directions as opposed to three the 3D tyre was capable of.

The new development here is the addition of a transverse sipe designed to offer more lateral grip by stabilising the rigidity of tread blocks when forces are applied in different directions. These straight parallel sipes are intended to complement the multiple s-shaped sipes present in the previous generation by adding additional bite points perpendicular to the direction of motion. As a result the new design reportedly features 33 per cent more edges too.

Functionalised polymers

In addition to the extra grip and stability offered by these mechanical design modifications, Dunlop’s engineers have also developed a new compound featuring “functionalised polymers.” What this means is that new compound bonds the filler material to the rubber polymers in the compound at the molecular level. In conventional compounds filler molecules (commonly material such as carbon black and silica) have a tendency to coagulate, which generates heat and in turn increases rolling resistance. In contrast the bonding properties present in Dunlop’s functionalised polymers is said to propagate better heat distribution and therefore rolling resistance, but not at the expense of wet grip.

“Our tread compound is designed to evacuate water quickly and efficiently by eliminating turbulence in the tread grooves. The compound’s functionalized polymers provide the optimum dynamic stiffness needed at different temperatures. These active ingredients ensure that the Dunlop [tyre] can deliver best in class grip on wet roads without compromising on snow performance. Our choice and mix of compound is tailored to maximise snow and wet performance – whilst still allowing an improvement in rolling resistance, benefiting fuel economy,” said Dr Bernd Loewenhaupt, director Consumer Tire development at Dunlop.

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