The tread is the surface of the tire that is in direct contact with the road. The tread has a pattern, which is determined by the type and direction of the special grooves. The use of a tread pattern improves the grip of car tires on the road surface and helps with steering in different weather and seasons.
The choice of the type of tread pattern should be based on the type of driving, the quality of the roads and the climatic conditions. This affects the safety of the ride as well as the wear rate of the car tire.
Winter tires have a distinctive tread. If you compare with summer tires, you can notice the powerful shoulder blocks that hold the car on a slippery road. But, the winter tires of the European type differ very little from the rain summer tires, only in the depth of the pattern. Winter tires are used at subzero temperatures, the presence of snow and ice on the road.
Every car tire model has its own unique, individual structure. This applies not only to tires made under the same brand name, but also to all manufacturers producing winter car tires. This is due to the fact that each tire model is assigned certain tasks.
For example, some manufacturers consider it important to make their tires as quiet and silent as possible, but these tires have a very poor off-road performance, but at the same time noisy tires can boast a very good cross-country performance on almost any road surface.
What are the similarities and differences between, similar at first glance, models of tires? How not to make a mistake and choose truly practical and optimal tires for your car? The answers to these questions will be described in detail in this article.
What is a winter tire tread
The tread of a tire refers to the protective layer of rubber on the surface of the profile, which has a certain pattern. It allows you to achieve an optimal point of contact with the road. Generally speaking, the tread has three main functions:
- Protection against damage;
- Drainage of water from under the wheel;
- Ensuring normal traction on slippery surfaces.
The tread consists of several elements:
- Rib. This is the central part of the tread. It is present on European summer, rain and winter tires. It may not be present on Scandinavian and off-road tires.
- The tread block (checkers). The main element of the pattern, provides traction. This is where the studs are mounted.
- The rips (sipes). Small notches on the surface of the “beads”. Responsible for improving traction.
- Gutter. A circular groove. Usually located in pairs on the sides of the rib. Some tires with an aggressive pattern may not have one.
- Groove. The grooves separating the tread blocks.
- The shoulder. Blocks arranged at the very edge of the tread pattern. In winter, it is better to use tires with well-developed shoulder blocks on snow-covered trails.
Types of winter tire tread patterns
Two parameters determine the differences in tread patterns:
The directionality of the tread pattern shows whether the grooves have a common vector. For example, directional tires have a single, V-shaped pattern that “looks” in one direction. The symmetry of the pattern indicates that the groove block on the left and right side of the tire is the same. This is how the tires are divided into inner and outer sections.
In practice, several varieties of pattern are used. Let’s consider the types more detailed:
- Symmetrical non-directional
- Symmetrical directional
- Asymmetrical non-directional
- Asymmetric directional
When mounting directional tires, follow the arrow that indicates the direction of travel of the vehicle. Asymmetric tires also have an inner/outer side indication.
Symmetrical non-directional tread
This is a tread with a uniform tread pattern across the entire surface of the tire. There is no direction or strictly defined sides. They are versatile and reliable tires at a low price. Ease of mounting and interchangeability (easier to control wear) will be an advantage. It’s also ideal for “spare” tires.
This type of tread is used for both summer and winter tires. However, the most popular use is in the dry and warm seasons. Rubber with a symmetrical non-directional pattern will suit those to whom it is important to drive comfortably rather than speed performance. If most of the planned trips – it is a quiet ride in the city limits, choose such a tread pattern.
Among the disadvantages are poor controllability at high speed and during precipitation. Getting the wheels in a puddle on the track on such tires can lead to loss of controllability.
Tires with this tread is a basic set of most new cars. A non-directional tread pattern that is uniform across the entire width is also used for off-road vehicles with a mixed driving cycle.
Symmetrical directional tread
Tires with a symmetrical directional pattern are easy to recognize – they have a distinctive herringbone pattern across the width of the tire. A clear direction of grooves is designed to divert water, snow mass and dirt in the area of contact of the tire with the road surface. Such tires are recommended for rear-driven cars, which are more prone to skidding on wet asphalt or snowy roads.
When mounting such tires, you should follow the rule: the top of the “herringbone” when rotating must touch the road first, that is, look in the opposite direction to the movement of the machine. For convenience, most manufacturers indicate on the sidewall of symmetric directional tires hints: an arrow for the direction of rotation and the inscription “Rotation”. This avoids improper installation.
Driving on summer directional tires requires full traction with the road, so it is better not to move out on the “dirt”. Among the disadvantages of directional tires are noted noisiness.
Asymmetric tires are used to improve the speed and maneuverability of the car. They have two sides: the outer part of the tire is made of rubber with a coarser texture, as it experiences more stresses than the inner one. This provides better cornering control.
The inner part has smaller tread beads and wider grooves. This better drains water and improves traction.
For proper installation, manufacturers sign the inner (Inside) and outer sidewalls (Outside).
What distinguishes these tires is their high cost. The purpose of application – riding on high-speed cars on asphalt.
Asymmetric directional tread
The rarest type of tread pattern. It combines all the advantages of other types of tread patterns: it drains water perfectly, holds speed, and does not deform during difficult turns. In the middle part of the tread there is a longitudinal rib, which helps to keep high directional stability. The use of these tires is optimal for those who want the same handling both in dry and wet weather.
Asymmetric directional tires are not universal: they require special care during mounting. Not only the inside and outside must be considered, but also the direction in which the wheel moves.
Types of tread by function
In addition to the pattern, there is also a division by type of tread. It is worth to understand this diversity separately. First of all, we should mention friction and studded tires.
Studded tires work due to the presence of metal studs in the tread. They perfectly cope in situations where there is ice or snow in front of you. There are restrictions on operation in some conditions.
What are the tire studs for?
For extra stability when driving on snowy and icy roads, you can use winter studded tires. It is convenient if the weather in winter is variable, and ice can occur at any time, and the roads are cleaned irregularly. It will be useful to drive on studs for a couple of winters and beginner drivers.
The disadvantages of studding include noise and increased stopping distance on clean asphalt. On ice, on the contrary, the braking distance decreases.
Friction tires achieve optimal traction due to their tread structure, additional elements and rubber composition. At the same time, the tread pattern of this type of winter tire can vary.
In addition, friction tires are divided into the following varieties.
Scandinavian tire tread
This is a pattern with rectangular and diamond-shaped blocks. The distance between the tread elements is quite large. The lateral edges are sharper. The structure is softer than that of European tires.
The “coarse” pattern allows the tire to squeeze through ice or snow crusts with ease, prevent mud buildup, and brake better on ice – a good option for driving on poorly paved streets and out of town.
European tire tread
Designed for “soft” winters and snow-cleared roads. In heavy snowfall, European tires will be problematic to drive on.
Such tires effectively remove snow and water. The pattern is not rough, and the edges have a smoother transition. European rubber is harder – the use of rigid material increases wear resistance. European-type tires “live” for about 5 seasons, unlike Scandinavian tires, which need to be replaced every 2-3 seasons.
What tires are better for winter: studded or friction?
|Driving conditions||Rubber type and tread pattern|
|Driving on asphalt||V-shaped contact pattern with a rigid middle or asymmetrical, without spikes with a high speed index and a shallow tread depth|
|Driving on snow||Classic or v-shaped friction-type tread, consisting of small “cups”, with many longitudinal and transverse grooves|
|Driving on ice||Up to -20°C(-4°F): directional studded with a small opening angle or classic tread with a minimum number of large grooves
Above -20°C(-4°F) : friction rubber with similar geometric properties
Which winter tire pattern is better: symmetrical or asymmetrical
It’s impossible to say definitively which pattern is better for winter tires, because everything depends on the condition of the road surface. When the road is deep snow drifts or heavily rammed snow, you should give preference to directional asymmetric tires that stand out with their aggressive design projector.
If you intend to drive on roads with shallow, fairly melted snow, constantly melting, you should choose non-directional projector. When water on the road alternates with deep drifts, asymmetric non-directional tires are installed, characterized by lateral hooks that rake away snow while draining water through drainage channels.
Which winter tire is better: directional or non-directional
Choosing which tread pattern of winter tires is better, it is necessary to understand where the vehicle will be used more often. If the car will drive on the city roads cleared of snow with reagents, it is better to buy tires with asymmetric low-noise projection. However, going out of town on non-asphalt roads, it is almost impossible to get out of snowdrifts.
The best option for the Russian winter is a symmetric directional pattern, which helps to form directional stability and shoveling snow. True, you will have to put up with a high level of noise, but when cross-country ability is more important, it’s not a problem.
Features of the tread pattern of winter tires
Let’s review some of the differences from summer tires:
- The pattern height is always greater. Even the simplest tires have a depth of 7-8 mm and a minimum residual of 4 mm, which is much greater than that of summer tires.
- The presence of large blocks of different shapes, which makes it possible to work more effectively in the snow.
- There are special cuts (sipes), which provide a better grip on slippery surfaces.
- Side shoulder blocks are very noticeable
As already mentioned, the sipes are an important design element. They improve traction by providing the blocks with extra mobility. Because of this element, friction tires are often as effective as studded tires. A tire may be fitted with several different types of sipes.
Special mention should be made of the pumping blades. They are located on the shoulder blocks. The main feature is the widening of the notch closer to the outer edge of the shoulder. This allows water to drain reliably from under the vehicle.
How to install winter tires depending on the tread
The correct installation of the tires determines their efficiency and safety. It is necessary to take into account the features of the tread. Let’s list the main nuances:
- Symmetrical non-directional tires can be installed as desired without restriction. You can choose any tire and interchange between them.
- Symmetrical and directional tires. Mounted according to the direction indicated by the arrow and the inscription ROTATION.
- Asymmetric non-directional tires must be fitted as indicated by outside, inside. The direction of travel is irrelevant.
- Asymmetric directional tires are the most demanding to fit. They must be mounted according to the direction of travel and respect of the sides (inside/outside).
Remaining winter tires tread depth
According to the technical regulation on the approval of wheeled vehicles for winter tires there are restrictions on the minimum tread depth of 4 mm. This applies to tires marked as winter or M+S. Usually there are manufacturer’s marks, specified a minimum allowable depth of 4-6 mm
It is not safe to drive your vehicle if the tire is worn more than normal.