Studded or studless winter tyres? New research explains which grips better on ice

Ice can be slippery even without melting

Saarland University researchers Achraf Atila, Sergey Sukhomlinov and Martin Müser published a study in the journal Physical Review Letters, titled “Cold Self-Lubrication of Sliding Ice”, that challenges the conventional explanation for ice’s slipperiness.

Until now, low friction on ice has been attributed mainly to pressure and heat generated by friction, which melt a thin layer of water on the ice surface.

However, the researchers’ molecular simulations showed that sliding contact can disrupt ice’s ordered crystal structure even without conventional melting. This creates a liquid-like molecular layer on the surface that can reduce friction. Whether very low friction develops also depends on the properties of the material in contact with the ice and the movement of water at the interface.

The finding does not prove that one tyre type is better than another, as the researchers did not test car tyres. It does, however, show why grip on ice cannot be predicted from air temperature alone.

Studs provide an advantage where rubber can no longer grip

The greatest strength of studded tyres is the ability of their metal studs to penetrate the surface layer of ice and provide mechanical grip. This becomes particularly important on smooth, polished ice, where friction between the tyre rubber and the surface is low.

Studless winter tyres take a different approach. Their soft rubber compound, which remains flexible in the cold, conforms to irregularities in the road surface, while numerous cuts in the tread, known as sipes, create additional biting edges.

The most challenging conditions occur near 0 °C, when water is present on the ice surface. In these conditions, the mechanical grip of studded tyres can provide a significant advantage both under braking and when cornering.

The situation changes in extreme cold. Ice generally becomes harder, making it more difficult for studs to penetrate its surface. Nordic studless winter tyres retain their flexibility thanks to a special rubber compound, narrowing the grip gap between the two tyre types.

This does not mean, however, that studless winter tyres are automatically better at -15 °C, for example. There is no fixed temperature threshold, because the outcome depends on the ice’s surface structure, the tyre model, stud design and rubber compound.

Winter tyre tests confirm the advantage of studs on ice

Finnish magazine Tekniikan Maailma’s 2025 comparison test featured seven studded tyres and seven Nordic studless winter tyres in size 205/55 R16.

Braking on ice from 50 km/h, the Bridgestone Blizzak Spike 3 recorded a stopping distance of 32.3 metres. The best studless tyre, the Michelin X-Ice Snow, needed 45.6 metres to stop. The gap was 13.3 metres, or more than 41 per cent of the studded tyre’s braking distance. That is a large enough difference to alter the consequences of an accident involving an unexpected obstacle.

At the same time, the test showed that results can vary considerably even within the same tyre category. Some studded tyres braked noticeably worse on ice than the best models in their category. Having studs therefore does not automatically guarantee good grip. Tyre construction and the specific model are at least as important.

The balance shifts on snow and asphalt

On snowy roads, the advantage of studs diminishes because the metal studs may not reach a sufficiently firm surface underneath. Grip then depends mainly on the tread pattern, rubber compound and the tyre’s ability to bite into snow.

A high-quality Nordic studless winter tyre can perform as well as, or even better than, a studded tyre in these conditions.

On wet asphalt, however, studs do not offer the same benefit as they do on ice. They increase tyre noise and wear down the road surface, while studless tyres generally provide a quieter ride.

It is important, however, to distinguish between Nordic and Central European studless winter tyres.

Central European winter tyres focus primarily on wet and dry asphalt, whereas manufacturers develop Nordic models for cold weather, snow and ice.

Swedish magazine Teknikens Värld’s 2025 comparison test confirmed the difference: Central European tyres performed strongly on wet asphalt but fell significantly behind Nordic winter tyres on ice.

In real winter conditions, the toughest driving situation matters

For drivers, the question is not just about braking distances on ice. A single journey can include dry asphalt, slush, compacted snow and unexpected black ice.

For those who drive mainly in cities and on well-maintained main roads, a high-quality Nordic studless winter tyre may be the more sensible choice. It offers good winter grip, less noise and greater ride comfort.

But if a daily journey involves rarely maintained side roads, icy inclines or road surfaces that have frozen in the early morning, studded tyres provide an additional safety margin.

Tyre age also matters. A studless winter tyre with a hardened rubber compound loses grip, while a studded tyre with worn or missing studs can no longer provide its original level of grip.

A new, high-quality studless winter tyre can therefore be safer than an old, worn studded tyre.

Physics offers no universal winner

The Saarland University study does not change the results of winter tyre tests to date, but it adds to our understanding of why ice becomes slippery in different conditions.

The mechanical advantage of studded tyres on smooth ice remains. The strengths of studless winter tyres, meanwhile, are their versatility and their ability to achieve very good grip without metal studs.

Tyres should be chosen for the most challenging road conditions, rather than the average winter day. If driving on ice is a regular requirement, studded tyres are generally the safer choice. On well-maintained roads, Nordic studless winter tyres may offer a more balanced solution. In winter, safety is not determined by how well a car drives on dry asphalt. A single icy bend can be decisive.