Many drivers often have questions regarding the use of winter studded tyres. Here, we will discuss the history and design of studded tyres, the various advantages and disadvantages they offer, as well as an overview of their legality in different countries.
The use of studded tyres is prohibited in many EU countries, except in some special cases (such as racing).
The History Of Studded Tyres
Studded tyres, in their modern form, were first used in Scandinavia in the 1950s. These were used to provide improved grip on ice and snow-covered roads. This was followed by a rapid expansion in the use of studded tyres in the 1960s and 1970s, which involved widespread adoption across Europe and America.
However, in the late 1970s, studies started to appear with regards to the impact such tyres can have on the roads. This was most widely seen in America but, after the results of these studies, many manufacturers were obliged to remedy the defects. In other cases, governments outright banned the use of studded tyres.
The Structure Of The Tyre And Studs
At its simplest, a studded tyre is a winter tyre with metal studs inserted into its tread. The exact number of studs will depend on both the size and model of the tyre in question, but figures typically range from 60 to 120 studs.
Each stud weighs approximately 2 grams and consists of two parts. The base is made of either aluminium, steel or plastic, while the stud component itself is made of tungsten carbide, due to its extreme resistance to abrasion. On most studded tyres, these studs protrude above 1.5 mm above the tyre surface.
There is, however, great variation in both the shape of the base and the length of the studs themselves. Most will be between 10-15 mm long (remember that only 1.5 mm of this extends past the tread surface) although they can be up to 30 mm deep in the case of truck tyres and other larger models. Structurally, these tyres do not differ from radial tyres, although the tread thickness under the grooves is often larger, as this ensures separation between the steel belts (part of the tyre’s construction) and the stud base. If this layer was too thin, this would enable more salt and water to penetrate the tyre and corrode the internal belts.
As for the construction of studded tyres, the studs are inserted into the tyre tread after vulcanization. If studs become worn or lost, it is often possible to have them replaced, rather than having to buy a new set of tyres.
Features of Studded Tyres
Studded tyres are intended for driving on a layer of ice or compacted snow. On these surfaces, their performance is unrivalled, making them a superior choice to other solutions. In other weather conditions, such as wet surfaces, they perform significantly worse than standard winter tyres. This results in a noticeable reduction in safety and, even on deep, fresh snow, studded tyres can perform less well than expected, due to the smaller number of sipes.
Despite the great progress made with studded tyres, it is not possible to ignore the impact that studded tyres have on road conditions. The studs currently in use - although less impactful than those used a decade or two ago - continue to cause the deepening of ruts, degradation of roads and damage to the road markings. The interaction between studs and asphalt causes a change in its roughness at both microscopic and macroscopic levels. This can lead to a reduction of grip in the summer, due to the surface polishing effect, and in the winter. Similarly, When driving on dry asphalt, the studs can still cause mechanical damage to the belt of the tyre.
A close up view of a studded tyre.
Where Does It Make Sense To Use Studded Tyres?
When it comes to winter roads, there are two standards of maintenance, known as “white road” and “black road”. The white road standard is used in environments with harsh winter conditions, particularly where the weather is consistent for a few months. This includes the likes of Scandinavia, where the removal of ice and clearing of the carriageway would be too expensive and difficult. As a result, the roads are cleared without removing the layer of compacted snow. In these conditions, solutions are needed for extra grip, which is where studded tyres are used.
For warmer countries, where snowfall is less common and irregular, black road standards apply. This is where the roads are cleaned of the snow entirely, ensuring there is no need for additional grip (other than the levels already offered by a winter tyre). The United Kingdom has a very warm climate in relation to Scandinavia and utilises black road standards. As a result, there is no need to use studded tyres when driving in the UK. In fact, aside from a few exceptions, studded tyres are illegal in this country.
Which European Countries Allow The Use Of Studded Tyres?
If you’re travelling through Europe during the winter the use of studded tyres are permitted, depending on where you are. European countries that permit the use of these tyres include:
Typically, these countries will set periods where the studs can be used. Some will even require the vehicle to be appropriately marked to indicate that studded tyres are in use. There will also often be a separate speed limit for cars using such tyres.
In most Scandinavian countries, where the use of studded tyres is permitted in winter, a charge is made for driving into many cities on this kind of tyre. This is because cities will often have better road conditions, similar to black road maintenance, and the studs will just cause damage. Furthermore, studs may fall out, which creates further danger on the road, especially when travelling at high speeds.
As a result, there is no need to use studded tyres when driving in the UK. However, if you are driving in other countries, you may wish to look up their regulations and the expected weather conditions. If you’re facing tough winter climates, than studded tyres can provide you with extra grip. For everything else, traditional winter tyres will provide more than enough control.