Reading Tire Patterns: What Affects a Tire’s Behavior.
Would you like to determine at a glance how this or that car tire will behave on the road? Tired of just taking the word of salesmen, who trumpet incomprehensible terms, telling you about the characteristics of tire models? Do you want to be able to determine by a single picture whether this tire is suitable for you or not? If you answered yes to at least one of these questions, then this article is for you. Today we will consider the main types of tread patterns of passenger car tires, and let’s analyze which elements are the key ones that determine the behavior of the rubber in different road conditions. Of course, it’s not just the design that ensures tire performance. The carcass strength and the composition of the rubber compound are also important. But today we won’t speak about them. This article will focus on the composition of blocks and slots. How Different Design Concepts Affect Tire Behavior
Over the long history of automobiles, a huge variety of tire options have been created for their wheels. Currently, four main types of pattern prevail in mass production. Let’s consider their advantages and disadvantages in more detail.
Symmetric directional pattern
In such tires, the inclined grooves seem to converge to the center in the direction of rotation. The figure perfectly copes with removal of water, slush and snow mass. The slanting grooves promptly remove fluid from the contact patch. Such a design is most often chosen for high-speed tire models, which are assigned the task of protection against aquaplaning in conditions of operation at higher revolutions. The disadvantage of such tires is higher noise level, as compared with non-directional counterparts, and poor stability on uneven surfaces. But they perfectly keep the set course on asphalted city roads and intercity highways. When installing such tires, it is obligatory to observe the specified direction indicated by an arrow on the sidewall and the inscription “Rotation”.
Symmetrical non-directional pattern
Tires with such design are considered to be the most universal. Such tires are most often installed on new cars. Their advantage is that they can provide a high level of comfort, stability and safety on various types of roads. These tires are best suited for calm sedate drivers who have to drive a lot in the mixed cycle. The disadvantages include low efficiency of this rubber when driving on wet roads at high speeds. Fast water evacuation is not their strong point. But they can be installed on any side and on any wheel. This facilitates the replacement processes and allows you to periodically swap wheels, ensuring the even wear of the tire set.
The idea of such design appeared due to the fact that, having analyzed the load of different zones of the tire in certain conditions, the engineers came to the understanding of the need to zone the tread. Thus, the outer zone was endowed with more rigidity and resistance to deformations, which can occur during active maneuvering. And the inner section is responsible for drainage and protection against aquaplaning, so there are a lot of drainage grooves. At the same time, the center is rigid and dense, thanks to which it provides directional stability. Tires of this type are installed on high-performance cars. The disadvantages of this design include low efficiency at higher rpm and poor vibration damping due to the rigidity of the outer side. When installing, make sure that the “Outside” mark on the sidewall is on the outside and the “Inside” mark on the inside.
This is the most rarely seen option. It was developed in an effort to create multifunctional tires with efficient drainage and even load distribution on the surface. It would seem that here it is – a perfectly balanced option, but not everything is so simple. Difficulties for owners of such tires consisted in correct installation on the car with observance of both direction of rotation and symmetry. On the sidewall of such tires there is an arrow with the inscription “Rotation”, and designations “Inside” or “Outside”. But that is half the trouble, it is not difficult to deal with it. But what to do with selection of a spare wheel?
In general, the production of such tires was abandoned with time. Now it is almost impossible to find such design of rubber. Who knows, maybe in the future we may get back to asymmetric directional tires, when, for example, the technology of flat tires or means of restoration of damaged tires will be perfected.
The role of individual pattern elements
Now let’s break down the overall concept of a tread pattern into its individual parts. Let’s look at the most common design elements.
Solid or compacted center rib
The center rib The center of the tire is under the most strain at high speeds. Increased stiffness in this area ensures optimal directional stability on dynamic rides. You can expect excellent handling and responsiveness to steering signals from tires with this design element.
These are the main hydro-evacuation elements. They take the fluid to the rear wall of the contact patch, from where it is led out to the sides. The greater the surface area of the channels, the more efficient the drainage.
Multi-angle grooves on the tire surface enable water drainage even during hard manoeuvring.
Wide shoulder pads
Solid side pads help ensure stability and prevent slippage when cornering.
Small, wavy slots in winter tire blocks.
They are also called self-locking sipes. The essence of their work is this: when driving straight, they capture moisture and snow mass, increasing traction on a wet road. But when turning, these slots close, providing high tread stiffness and stability of the contact patch.
The name fully reflects the essence of these elements. Some snow can accumulate in the small notches adjacent to the drainage paths. This increases the overall traction properties of the winter tire, because the snow-to-snow contact is stronger than the snow-to-rubber contact.
Open shoulder grooves.
They are responsible for removing fluid from the contact area in the transverse direction. The drainage rate is increased if these grooves are wider than the slots or channels that adjoin them. In this case, water is pushed out due to a large pressure difference. Another engineering solution worth mentioning is the offset of the slots separating the blocks in different ribs and the use of beads of different sizes. Thanks to this it is possible to obtain a difference in the amplitude of the noises that occur during movement. As a result, the acoustic comfort of the tires is noticeably improved. That concludes our review for today. Stay tuned to know more and choose consciously. Source.
Tread of passenger tires, types of pattern and their classification
The tread is the outer element of passenger tires, which is designed to create an optimal contact patch, as well as additional protection from damage and punctures while driving.
This part of the tires varies in pattern and composition of rubber, each of which is designed for certain weather conditions and type of road surface. In this article, we will look at the most common types of them.
Table of contents:
Tires, depending on their design and the applied indentations in the tread pattern, change their characteristics. That’s why it’s important to know for which conditions and coatings this or that type of tread pattern is designed.
One of the most common types of tire tread. The applied indentations on the outer part of the slope are mirrored, so these tires can be mounted on the rim regardless of the side or direction of rotation. Symmetrical non-directional pattern has the most balanced characteristics in addition to the ease of installation: comfort and smooth running in the first place. Such tires also cost less than their more complicated counterparts.
This tread pattern provides the best diversion of water from the contact patch with the road of the car wheel. Symmetrical directional tires often have high speed indexes, which allows them to be installed on sports cars. These tires are mounted on the tire in a specific direction – there is a “Rotation” inscription on the sidewall of the slope, which indicates the direction of wheel rotation. Ideal for rainy weather.
Tires with this type of tread have excellent driving characteristics – the speed of shifting on these tires is usually higher in sharp turns and changing lanes. In addition, sports tires are provided with a reinforced sidewall, due to which the noise and comfort during normal driving is reduced. Asymmetric non-directional tires may only be fitted to rims in accordance with the “Outer” and “Inner” markings on the sidewall of the rim. The pattern combines some of the advantages of a symmetrical directional tire and a symmetrical non-directional tire.
The characteristics of such tires are almost identical to the symmetric directional pattern, but has a number of advantages – due to the reduced width of the inner side of the tread the car has better traction, and the outer part is used to clean the remaining contact patch. These tires are labeled “Rotation” with the direction of rotation, as well as “Inner” and “Outer” for mounting on the outside or inside of the disc. The price of such tires is usually the highest due to the complexity in their production.
Tire mounting scheme depending on the tire pattern:
Comparison of tread patterns for advantages or disadvantages:
|Type of pattern||Pros “+”||Drawback “-”|
|Symmetric non-directional||Maximum comfort Low price Easy to install and replace||Low speed index Worse handling than others shown|
|Symmetrical directional||Better handling Better water evacuation High speed index||High cost Noise levels|
|Asymmetric non-directional||Symbiosis of directional and nondirectional pattern Good water drainage and handling Good price||Average noise level Comfort Slightly less than non-directional symmetrical|
|Asymmetrical non-directional||Maximum handling Maximum speed indexes Best footprint water drainage||Difficulties with mounting at the tire fitting and changing tires Highest cost|
Tread pattern of summer tires
Summer tires are designed to operate in conditions of positive temperatures (above +5 ° C). Depending on the tread pattern and type of tread pattern, they are designed for different road surfaces.
H/T, H/P (Highway Terrain / Performance) tires
The most common light treads, which are designed for use on hard road surfaces (asphalt, concrete). This tread has excellent traction properties and low noise level on the above-mentioned surfaces. Excellent at removing water and road dust from the contact patch. Created for city and highway travel. Poorly cope with off-road surfaces and absolutely not suitable for winter conditions of operation.
Universal A/T (All Terrain) Tires
Tires are intended for mixed conditions of operation – equally good for hard surfaces and roads with dirt and gravel. Have a little more noise and less stability than their highway counterparts, but will take the owner in the mud or wet grass to the cottage or out of town. Usually the pattern on such rolls has a larger checkers, and the distance between them is greater, to better clean the contact patch of dirt.
M/T (Mud Terrain) off-road mud tires
These tires are designed to overcome extreme off-road conditions, stony roads, deep ditches with mud. The tread has a greater height and distance between the sections, so that it can be cleaned from mud more quickly. The design sometimes uses side grousers (part of the tread is transferred to the sidewall to improve traction in the mud and clearing). Such tires have a high noise level when driving at high speeds, concrete or asphalt roads.
Allowable residual tread on summer tires
As they wear, some of the tread wears down and becomes lower, which inevitably leads to a deterioration in tire performance. The legal limit is 1.6mm for car tires, 1.0mm for truck tyres and 0.8mm for motorcycle tyres. In addition, the manufacturer of many tire models provides an internal rim, located on the tread, upon reaching which the tire is considered unusable.
Tread pattern of winter tires
Winter tires differ from each other by tread pattern, as well as the difference in design. In total, we can divide these treads conditionally into three types: “European”, “Scandinavian” (aka “Arctic”) and “Scandinavian” studded.
“European” winter tires.
This type of tread is designed for mild winters and virtually clear of snow and ice roads. The composition of the rubber is softer than summer tires, but stiffer than the “Arctic” type. They are ideal for wet snow and rain. The tread has long diagonal slots, for effective water drainage and usually side grousers. The tread height is usually up to 8 mm.
“Scandinavian” or “Arctic” winter tires (aka “Velcro”)
This tread pattern is designed for harsh winters. The tires are made of soft types of rubber to maintain properties even in the harshest cold. The sipes along the tread blade are very tightly sliced, and the shoulder blocks have a sharp edge. The ideal hike for these tires is soft snow with little icing. The tread height of the new rollers is 9-10 mm.
“Scandinavian” or “Arctic” winter tires with spikes
Spikes are usually installed in addition to Velcro, which in addition to excellent traction on snowy roads gives an advantage on ice. With all this appears a huge disadvantage – driving on asphalt becomes less comfortable due to the increased noise. In addition, on hard roads during braking or sudden acceleration steel studs fly out of their seats and have to spend extra money to re-install them.
Allowable residual tread on winter tires
According to traffic regulations, the tire intended for use in winter, the tread should be no less than 5 mm. The manufacturers themselves admit that when the tread depth is below 4mm almost all traction characteristics are lost.
Tread depth varies for different seasons and types of tires. Summer tires have a tread depth of 7-8 millimetres and winter tyres have a tread depth of 8-10 millimetres. As tires wear down, their grip characteristics deteriorate. To learn more about how tire wear affects handling, follow this link.
Tire tread regrooving
Many car owners give their tires a second life by retreading them. There is much controversy surrounding this procedure, read on to find out “Can the tread be regrooved” and “What is the risk.”
Actually, there is nothing wrong with the tread-cutting procedure and the tire manufacturers allow it, but only on pitches where it is intended by the design. To determine whether it is possible to deepen the groove on the tread of your tires is simple – tire manufacturers put a marking “Regroovable” or the letter “U” on the sidewall, which is the permission to extend the life of the tread. A layer of rubber is specially added to the design of the aforementioned rollers to add recesses to the webbing. If your tire does not have these symbols, it is forbidden to perform the procedure – it can lead to the destruction of the tire due to overheating or too thin height.
How to cut the tread
In order to cut additional depth on the tread it is worth to address a special service or tire fitting shop that deals with this procedure. If you do decide to do it yourself, use a tread-cutting machine such as the RILLFIT S-146B. This device costs about $600-700, so it’s not really a good idea to buy it for a one-time procedure.
Tread of passenger tires, types of pattern and their classification was last modified: April 25th, 2017 by abc-tyre