Are Wide or Narrow Tyres Best for Winter?

In winter, in harsh conditions you need the best tyres possible to cope with different hazards on the road. Luckily there are many winter tyre options to choose from. Sometimes the choice can be so big that some factors may confuse buyers. One such option are wide and narrow tyres. Which ones are better for winter? Keep reading to find out.

In this article, we will look at the various conditions you can face on the road, as well as situations where narrow or wide tyres are better than the alternative. This includes a look at some important factors, including:

• Winter has the largest variety of surface conditions, meaning that the roads could be dry, wet, covered in snow, ice mud and slush, creating a need for the best winter tyres.
• On soft surfaces, such as deep snow, wider tyres are better, as smaller tyre pressure prevents the wheels from getting stuck in the snow.
• Narrow tyres, on the other hand, are superior on hard surfaces, where the increased pressure results in greater grip.
• If you often drive on roads covered in hard snow or ice, typically found on infrequently maintained local roads, it's better to fit narrow tyres.
• If you drive on main roads and city streets, which are typically well maintained, it is better to use standard tyres.
• As for wide tyres, these only excel in deep snow, which is a surface that the average driver will rarely experience, if at all.

To be able to explore these factors, it is necessary to understand certain physical principles. Let’s start with a simple example. It is well known that it is hard to walk on ordinary ice. This is due to the lack of grip between their shoes and the ice. Wearing skis or snow boots, with a larger surface area, make little difference. Ice skates or crampons, however, allow people to move relatively freely.

In deep snow, on the other hand, skates and crampons serve little purpose. Yet skies and snow boots will prevent you from sinking into the snow, allowing you to move around on the surface.

As you can see, the key to efficient movement on winter surfaces is to exert the right amount of pressure on the ground. This directly depends on the size of the contact area that exists between the person and the surface. For driving on ice, very high pressure is required (and thus needs a minimal contact area) while deep snow requires a minimum amount of pressure (spread over the maximal possible contact area).

Common examples of developments in the motoring world include:

• Motorcycles that race on ice tracks are fitted with metal studded tyres.
• Ice rally cars also have studded tyres.
• Vehicles used to travel in very deep snow, such as trucks in the Arctic regions, have huge tyres. These are over a metre in diameter and are around half a meter wide filled with air pressure of 0.2 bar - ten times less than ordinary off-road vehicles.
• Vehicles such as snowcats and snowmobiles use caterpillar tracks, which offer a broad contact area. This ensures that the vehicle will not sink, even when crossing over the softest, powdery snow, and neither will it start to skid.

In short, the unit pressure on the ground should be your main factor for choosing tyres. For ice, the pressure should be as great as possible, while deep snow requires as little as possible.

What conditions might you encounter when driving a car on winter roads?

As stated earlier, winter often has the biggest variety of road conditions, compared to the other seasons. On a given winter road, you may have to deal with the following surfaces:

• Dry asphalt
• Damp asphalt
• Wet asphalt with a layer of water or puddles
• Asphalt with fallen leaves and mud brought by water or by vehicles driving out of fields.
• Deep, dry, loose snow
• Icy, frozen, loose snow
• Unsmoothed hard snow
• Smoothed hard snow
• Sticky, wet loose snow
• Melted snow, sludge and slush
• Clumped and grainy snow
• “Black ice” 
• “White ice” 
• Ice with snow and icy sludge

In winter, you may also encounter layered surfaces. For example, a lower layer of ice or hard snow (which offers the worst possible grip) might be underneath an upper layer of dry or wet loose snow (providing high resistance to movement). 

Other factors you need to consider include the environment you’re driving through. This can include:

• Forests
• Bridges
• Flyovers
• Tunnels in residential areas
• Roads sprinkled with sand, salt, cinder or grit

All of these need to be considered, as the conditions you expect to encounter the most can influence your choice of winter car tyre. When driving, the level of grip is also affected by the unevenness of snowy and icy surfaces, such as icy ridges, frozen ruts or bumps, as well as potholes formed by both snow and ice.

How to choose the right tyres for particular road conditions

Of course, it is next to impossible to prepare for the exact road conditions on any given journey. It’s highly likely that a long trip could encounter numerous such surfaces. It is impractical to change your winter tyres this frequently. For most drivers, it is better to have winter tyres that cater to the most common and frequent conditions in the areas they drive.

Generally speaking, it can be assumed that wider tyres will be better on a soft surface, as they prevent the vehicle from sinking. In the case of hard surfaces, narrow tyres can be expected to offer superior performance, as they increase the pressure exerted on the surface, improving grip as a result.

In the very toughest road conditions, it is recommended to always use winter tyres designed for extreme road conditions. These have a width of two, or even three, sizes smaller than your summer tyres.

These tyres offer enough traction to get you through most cases without the need for snow chains. Tyres of this type can be used for some time with reduced air pressure (but not less than 1.2 bar), which will increase the contact patch by as much as 100% (when dealing with soft surfaces). This effectively provides the same effect as if the tyre was twice as wide.

Such tyres are only made by a few manufacturers, typically the largest corporations, including Goodyear, Bridgestone and Continental. They are also some of the most expensive tyres on the market.

Which tyres are “wide” and which are “narrow”?

When labelling tyres with terms such as “wide” and “narrow”, it is always useful to establish a baseline width. This can be used to create a reference point, as any tyre different to this will be wider or narrower in comparison.

For every model of car, there are usually 3 tyre widths permitted by the manufacturer. For summer tyres it is best to use the widest of these. What is important, however, is that the tyres you use keep within the directions provided by the manufacturer (usually in the car manual).

When choosing wide winter tyres, you should use the largest width permitted by the manufacturer, rather than exceeding these pre-set limits. The same can also be applied to narrow tyres - they must not be smaller than the permitted widths for your vehicle.

If you don’t stick to the sizes declared in the vehicle manual, the car may be declared unsafe during a police check or technical inspection. In case of an accident - even if the incident in question was not your fault - you may also invalidate your third-party or comprehensive insurance. This is because changing the tyres to an unsuitable size will be deemed to be an impermissible action.

Wide or narrow tyres for winter? Summary

The harsh and varied conditions that winter brings along could cause drivers to change their winter tyres several times during that time of the year. So for the sake of practicality, some sort of compromise must be met when it comes to the width of the tyres.