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Winter tires

The first winter tire saw the light in 1934 thanks to the efforts of Finnish tire maker Nokian. Claw-shaped tread patterns, special compounds and sipes are just some of the innovations….and it certainly does not end there

Paolo Ferrini

Eighty years in the making

Winter tires, a constant headliner in recent years and an essential part of a vehicle’s equipment, nowadays even for Italian motorists, came to light eighty years ago in Scandinavia where, just as today, the rigors of the Northern winter certainly played a major role.

A Finnish company, Suomen Gummitehdas Osakeyhtio (today Nokian), claimed the production of the first tire of this kind back in 1934, when they unveiled a specialized truck tire named Kelirengas, which, thanks to a sturdy tread, was able to cope with the most extreme winter conditions. Its development was largely due to a partnership between August Kelhu, a Turku based tire dealer, and the company’s “father” and founder Erik Sundqvist, head of sales at Gummitehdas.  

At the time, the Kelinrengas was a truly revolutionary tire for driving on North European winter roads. Until then in fact, the tires used on the narrow snow-clad roads of Scandinavia were similar to summer tires and, in the proximity, for example, of a snow-covered uphill stretch, forced the driver to get off the vehicle to fit snow chains. A solution was sorely needed because, despite the poor conditions of the roads, goods still had to be delivered at any time of year.

Following the success of the Kelirengas, and the growing development of private vehicle ownership, the scene was set for a further development: passenger vehicles too needed specialized tires. Consequently, in 1936 the Finnish company developed and started producing a smaller winter tire, suitable to equip motorcars: thus, the first winter tire, the Hakkapeliitta, came to life.

Eighty years ago, roads as well as cars were certainly not comparable to what we have nowadays, and therefore required the design and development of winter tires, whose main characteristics were structural durability and superior handling on snow and ice. This resulted in producing stiff compounds, rather similar to what was used on summer tires, but with a remarkably different tread pattern with diagonal grooves designed to guarantee a “claw-like” grip on soft snow or mud.



The winter tire goes south

Over the years, the interest around snow tires, as they were called up until not long ago, spread to southerly latitudes. One of the first companies to seize the opportunity was Continental, in Germany, which by the end of Autumn in 1952 organized, as a demonstration, a crossing of the Gotthard Pass completely covered in snow using cars equipped with tires devoid of any metallic support to aid grip on snow and ice. With snow chains and studded tires left home, the expedition, consisting mainly of front engine and rear wheel drive vehicles only, easily overcame the snow-clad Alps thanks to an innovative claw-like tread pattern that paved the way for the modern winter tire: the Continental M + S (mud + snow, a marking that would soon know great success).



Superior tires for better roads

Up until the 60’s, grip in snowy conditions was mainly entrusted to large tread blocks arranged diagonally to the rolling direction of the tire, and wide grooves for snow and water displacement, similarly to what extreme off-road tires or wet tires in Formula 1 do nowadays. This solution, however, made winter tires very noisy and rather uncomfortable (especially when used on tar roads).

Designers, therefore, soon began to work on new tread patterns, trying to reduce the size of the tread blocks, and especially developing coarse block structures with a greater number of edges as well as innovative new compounds. These partially compensated the reduced grip of the tires compared to studded models providing a more comfortable ride, virtually silent. The Continental M + S 18, introduced in 1963, certainly stood out as the first interchangeable winter tire, suitable to be fitted on every wheel.



Compounds and sipes               

The technological breakthrough came in the early seventies when research teams started to focus more on compounds rather than tread patterns. In 1971 Goodyear unveiled the first Ultra Grip generation (over 50 million units sold since then in Europe alone) and the following year it was Continental’s turn to launch its Contact M+S 729, the first model of the successful Contact family, as well as the first studless winter tire in history. The tread pattern was less “aggressive” to guarantee a higher mileage and lower noise levels, while the compound and lighter grooves on the tread, forerunners of today’s siping technology, played a fundamental role in a tire’s performance in winter conditions.

During the following decades, these lighter grooves grew in number and decreased in size, becoming progressively thinner and thinner. But it wasn’t until the early 80’s that the term sipes was heard, thin elastic slits cut across a tire’s tread that adapted to the road surface to improve traction and braking in wet or icy conditions. 

Siping took on new forms over the years. Sipes that run outwardly over the tire shoulders, which bear a great responsibility when it comes to traction and grip, further increase the tire’s, and consequently the vehicle’s, handling. As a matter of interest, if all the sipes on a 195/65 R15 tire were placed side by side in a straight line, they would cover a distance of 2 kilometers (1967 meters to be precise).  At the turn of the new century, the attention of engineers shifted on the behavior of winter tires on dry and wet roads, which was improved without diminishing their efficiency on snow and ice, using new and innovative silica-based compounds. In 2000, this allowed Continental to launch its WinterContact TS 790V, the first winter tire with speed symbol "V", which meant that a tire could be used at a speed of 240 km/h (on dry roads obviously!).


Dual-compounds, low profile and “connected”                                                                             

Nowadays, manufacturers are developing special compounds, low profiles to meet an increasingly diversified market as well as asymmetrical and unidirectional tread patterns to get the most out of winter tires designed for sports cars and sedans, specific winter tires for SUVs and even tires able to interact with on-board electronics. The Dual Compound is, for example, a Pirelli patent that consists of a softer outer compound able to guarantee superior performances and a harder compound in the central portion of the tread ensuring a safe ride even at high speed. The aim is to ensure both an excellent handling on dry roads and the best possible performance on snow without affecting safety parameters.


Ongoing developments                                                                                             

Far from being over, the development of winter tires continues relentlessly. In 2014 Nokian Tyres, for example, presented the prototype of a revolutionary winter tire that allows the driver to push out studs from the tread blocks and pull them back when no longer needed, all at the touch of a button. This new “studded/studless” tire combination allows the driver to change at any time the set-up of his car according to road conditions.

For its part, Continental is about to launch its all-new WinterContact TS 850 P with a tread entirely made with rubber produced from the roots of dandelion, an important step towards a more sustainable production that is less dependent on traditional raw materials.

Probably, these are just two of the many innovations on which the tire industry is working to improve traction and handling in critical conditions. In recent years, however, consumers have become more attentive to environmental issues, to low rolling resistance, noise levels and comfort. Over the past decade, technological development has been making great strides also in these areas.

All computers in large companies’ research centers are constantly testing the characteristics of new tires, therefore making these tests and simulations more technical and precise. One thing is sure, however; despite time and technical developments, no machine can develop a new idea. Creativity will always be the exclusive property of Man.

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