In winter, drivers want the best tyres to cope with the harsh conditions. There are many options and variances to choose from, which can sometimes make choosing the right winter tyre more difficult than originally assumed. One such factor that confuses many drivers is whether to opt for wide or narrow tyres?
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, including dry, wet, snow, ice mud and slush environments, ensuring a need for the best winter tyres.
- On soft surfaces, such as deep snow, wider tyres fair better, as the smaller 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 with compacted snow or ice, typically found on infrequently maintained local roads, it is more preferable to fir 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.
Our Conclusion: Your choice of winter tyre width should depend on the most common conditions you face while driving. We have provided more detailed information about this to help you make this decision.
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 for a person to walk on ordinary ice. This is due to the lack of adhesion between their shows and the icy surface. Wearing skis or snowshoes, with a larger surface area, make little difference. Ice skates or crampons, however, allow people to move relatively freely.
Source: Goodyear. In winter we encounter a wide variety of road conditions,
for example compacted snow together with ice.
In deep snow, on the other hand, skates and crampons serve little purpose. Yet skies and snowshoes 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 area of contact that exists between the person and the surface. For 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 maximum contact area).
With people, this is achieved via skies and snowshoes (for a wider contact area and minimal pressure) and ice skates and crampons (for a small contact area and a high amount of pressure). For vehicles, this is achieved via wide and narrow tyres.
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 (500 mm) wide with an 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 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, as can be seen by the various examples above, is the main factor for choosing tyres. For ice, the pressure should be as great as possible, while deep snow requires as little as possible.
Source: Goodyear. Before setting out, check the technical condition of your tyres.
What conditions might you encounter when driving a car on winter roads?
As stated earlier, winter often has the biggest and widest variety of road conditions, compared to the other three 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 carried by water or by vehicles driving out of fields.
- Deep, dry, loose snow
- Icy, frozen, loose snow
- Unsmoothed compacted snow
- Smoothed compacted snow
- Sticky, wet loose snow
- Melted snow, sludge and slush
- Clumped and grainy snow
- “Black ice” / frozen moisture
- “White ice” / smooth compacted snow with ice underneath
- Frozen water with snow and icy sludge
In winter, you can also encounter layered surfaces. For example, a lower layer of ice or compacted snow (which offers the worst possible grip) might be underneath an upper layer of dry or wet loose snow (providing high resistance to movement). The variation in both lateral and diagonal direction also needs to be taken into account, as there could be different surfaces on both sides of the vehicle, or icy and sludgy ruts.
Other factors you need to consider include the variation of environments along any particular route. This can include:
- 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.
Source: Goodyear. In the high mountains area, snow chains fitted on the tyres may prove useful.
How to choose the right tyres for particular conditions
Considering the great variety of possible conditions, it is hard to give a single correct answer to the question regarding narrow and wide winter tyres. What can be ascertained, however, is that there are a number of general rules everyone can use to choose the tyre width that suits them best.
In some cases, just changing the tyre width may not be of any help if other factors, described below, are not taken into account.
Optimum tyres for particular surfaces
- Dry asphalt and damp asphalt. For roads in good condition, it is best to choose wide tyres. However, is the asphalt is uneven or has holes and ruts, a narrower tyre will offer more grip.
- Wet asphalt with a layer of water or puddles. It is generally best to use narrow tyres on these surfaces, preferably with excellent water expulsion (to avoid the likes of aquaplaning). The wider the tyre, the more water needs to be expelled, thus making a thin, narrow tyre more preferable.
- Asphalt with leaves or mud. If the road is covered with fallen leaves or mud, narrow tyres perform better.
- Soft snow surfaces, such as deep, dry, loose snow and icy, frozen, loose snow, all have similar properties. Because they may sink or move, they provide limited mobility. As a result, a wide tyre with an aggressive block tread is preferential. Sipes in the tyre have little effect in these conditions and it’s often beneficial to use off-road tyres with a herringbone tread.
- Unsmoothed and compacted snow has reduced grip. The width of the tyre is not as important here as it is to have tyres with sipes and an aggressive tread design. An aggressive side edge, likewise, helps to ensure good steering.
- Smoothed and compacted snow, on the other hand, is a hard surface similar to ice, offering a significant reduction in grip. The best grip for this surface comes from zigzag sipes both along the route and in lateral directions.
- Melted snow, sludge and slush are all soft surfaces and behave similarly to deep dry loose now. Again, a wide tyre incorporating an aggressive block tread design offers the best performance.
- “Black ice” or frozen moisture, as well as ice under snow, are all falt and hard surfaces, offering noticeable reductions in grip. As a result, a wider tyre with good sipes is recommended. These sipes should be in a zigzag formation to offer the best grip both laterally and along the route.
- “White ice” or smooth compacted snow is a hard surface but is often uneven. This can cause problems maintaining the direction of travel, even when driving in a straight line. Because of the potential unevenness, it is best to use tyres with the highest profiles, such as 80 or 85. To raise the profile of the tyre, it will also be necessary to change the rim for a smaller one, perhaps by two sizes. Raising the profile this way - in a manner similar to plus sizing tyres (add link to Plus Sizing article) - gives the tyre a greater height between the rim and the road surface. As a result, it can absorb bumps better, thus offering an improved grip.
- Frozen water with snow, as well as icy sludge conditions, offer hard, rough surfaces. It is difficult to say what width of tyre would provide the optimum performance in these situations, but an aggressive tread design will help increase the grip.
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.
Source; Goodyear. Always choose tyres that suit your needs and driving style.
Which tyres to choose – wider or narrower?
When it comes to determining the surfaces you most frequently drive on, you should also consider what elements you need the most. Do you need improved mobility and traction, or do you need good steering and stability?
By identifying these basic criteria, you can start making the optimum choice of winter tyres:
- Maximum mobility and traction guarantee the best possible ability to move, even when in extreme conditions. This makes them useful in snowbanks and icy, hilly roads, where the grip on a snow-cleared road is of secondary importance.
- Maximum stability and steering, on the other hand, offers the highest degree of safety in all conditions. In these instances, the need for mobility and traction in extreme conditions are less important.
Similarly, you can also identify your basic needs as a driver in winter:
- Driving on motorways and other main roads, as well as in city centres, means you are usually driving on black asphalt. You will appreciate winter tyres the most when sudden snowfalls or black ice appear, or if you have to drive on local roads which are not cleared of snow. In these situations, it is best to use standard winter tyres with the same width as your summer tyres. If you need increased grip on ice, you can use tyres one size narrower.
- On the other hand, if you’re driving on local roads and small towns which are not served by main roads, with only an occasional journey on a clear surface, than you will have a different experience during a snowy winter. In these cases, long journeys could take place on roads partially or completely covered in snow. Under these conditions, a narrow winter tyre (with a width two sizes smaller) is recommended.
- If you have limited driving skills or experience on snow-covered surfaces, or just want to be sure you can through the harshest of conditions, should use winter tyres for extreme road conditions. In terms of width, these can be either one or two sizes smaller than your summer tyres.
- If you drive on a lot of mountain roads, are rarely-used local roads in areas with heavy snowfall, you may require specially selected tyres. This is because the chances of snow being blown onto the road, combined with the steep slopes mountains generally offer, require more specialised options.
In the very toughest snow and ice conditions, it is recommended to always use winter tyres 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.
Source: Goodyear. Driving in the snow requires appropriate skills and the right choice of tyres.
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, although cheaper models may come equipped with the narrowest tyres for economical reasons. What is important, however, is that the tyres you use keep within the instructions dictated 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 the 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
As you can see, there are a variety of possible configurations for the ideal choice of tyres, depending on the conditions. However, the harsh and varied conditions seen in the winter would cause drivers to change their winter tyres several times a week. For the sake of practicality, some sort of compromise must be met when it comes to width.
If you most often drive in hazardous conditions on icy roads, then narrow tyres are better for your safety. However, if you are driving on clear asphalt roads for most of the winter, it is recommended that you retain your standard tyre size. Of course, whichever tyre width you choose, it is absolutely vital that you stay within the range of sizes established by your vehicle’s manufacturer.
Author: Dariusz Wojdas