Although winter is often considered as mild in the UK, it gets harsher in some regions. Many drivers in such areas as well as motorists who travel abroad or to mountainous areas use or consider using winter studded tyres.
This article will explain what studded tyres are, guiding you through their history and design and presenting various advantages and disadvantages they offer. You will also find an overview of legal issues related to studded tyres in the UK and other countries.
What are studded tyres?
A studded tyre is a type of winter tyre which has extra metal studs inserted into its tread. The exact number of these studs depends on the tyre size and model but it typically ranges from 60 to 120 studs.
The studs give a much greater grip on roads covered with certain types of precipitation such as snow pellets or grains, ice pellets or crystals, graupel, hail etc. Such winter tyre studs provide extra safety in challenging conditions. They are particularly useful on hills and roads covered with crust or slush but also in wet climates with temperatures around 0 degrees where surfaces get wet and freeze.
The use of studded tyres is prohibited in many EU countries, except certain special cases.
The history of studded tyres
Studded tyres, in their modern form, first appeared in Scandinavia in the 1950s. Similarly to their current function, they were used to provide improved grip on ice and snow-covered roads. The popularity of studded winter tyres grew significantly in the 1960s and 1970s, which caused their widespread adoption across Europe and America.
However, in the late 1970s, studies started to appear with regards to the impact such tyres may have on the roads. The majority of such studies was conducted in the US. However, after the results were published, new laws appeared also in Europe. Therefore, many manufacturers were obliged to remedy the defects studded snow tyres had on the roads. In other cases, governments outright banned the use of studded tyres.
The structure of the tyre and 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, material that’s great for this 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 models for larger vehicles.
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 studded tyre manufacturing process, the studs are inserted into the tyre tread after vulcanization. If they get worn out or lost, it is typically 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. Their performance on such surfaces is unrivalled, making them a superior choice to other solutions.
However, in other weather conditions that do not involve ice and snow, such as e.g. wet surfaces, they perform significantly worse than standard winter tyres. This is due to the smaller number of sipes and therefore, driving on stud tyres in conditions that do not demand their use can result in a noticeable reduction in safety and, even on deep, fresh snow, studded tyres can perform less well than expected.
Implications for using tyres with studs
Although studded tyres have been greatly improved over the last years, their impact on the condition of roadways is still an obstacle that cannot be ignored. The studs currently in use - although less impactful than those used a decade or two ago - continue to cause road degradation by deepening ruts and damaging road markings. The interaction between studs and asphalt leads to a change in its roughness at both microscopic and macroscopic levels.
As a consequence of the surface polishing effect, this can lead to a reduction of grip in the summer and in the winter. Similarly, when driving on dry asphalt, the studs can still cause mechanical damage to the belt of the tyre.
Studded tyres in different regions and conditions
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 regions such as Scandinavia, where the removal of ice and carriageway clearing would be too difficult and expensive. There, the roads are cleared without removing the layer of compacted snow. In these conditions, solutions for extra grip are needed, which is why studded tyres are used.
For warmer countries, where snowfall is less common and irregular, black road standards apply. This means the roads are cleaned of the snow entirely, ensuring the contact of car tyres with the road surface. In these regions there is no need for additional grip (other than the levels offered by winter or mud and snow tyres).
Can you use studded tyres in the UK, then?
The United Kingdom has a very warm climate in relation to Scandinavia and relies on the black road standards. As a result, there is no need to use studded tyres when driving in the UK.
In fact, except for a few exceptions such as racing and off-road situations, studded winter tyres are considered illegal in the UK. Interestingly, the national legislation does not make specific reference to studded tyres but their use is not permitted in EU countries unless that country's law says so, like in the case of Nordic countries such as Norway or Iceland.
The reason why studded tyres are not allowed in the UK is because studs damage tarmac so if many drivers used them, it could significantly worsen the condition of the roads. Besides, due to the large amount of frictional resistance, they would wear down very quickly, especially if used on roads that are not covered with a certain amount of snow and ice.
Legality of studded tyres in Europe
If you’re travelling through Europe during the winter, be aware that the use of studded tyres may be permitted, depending on where you are. European countries that allow for the use of these tyres include:
- Sweden
- Finland
- Norway
- Italy
- Austria
- Switzerland
These countries typically specify periods when the studs on tyres can be used. Some may 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 road damage. Furthermore, studs may fall out, which creates extra danger to the road surface, especially when travelling at high speeds.
Considering all the above, usually 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, then studded tyres can, indeed, provide you with extra grip. For everything else, if you use good traditional winter tyres and carry snow chains, you will have more than enough control.