When it comes to car tyres, the right tread is a very important decision. After all, this is the part of the tyre that is in constant contact with the road surface. Subsequently, the various features and choice of tread can greatly alter both the properties of the specific tyre, as well as how the car handles as a result.

The right choice of car tyre tread, for instance, can help:

  • Improves the amount of traction
  • Improves the car’s ability to steer
  • Influences the durability of the tyre itself

The right choice in tread patterns, similarly, helps influence a number of key factors, including:

In this article, we will go over the various factors and design features that help that feature in treads tyres use for a number of reasons. By identifying these features, you can understand how a given tyre is designed to improve specific parameters.
 
For a quick overview, we have also prepared this short video:

Tyre Tread Features

Sipes. These are the narrow voids and passageways on the tyre lugs, usually around 0.3 - 1.5 mm thing. Their main purpose is to improve the tyre’s traction on wet surfaces, as well as snow, channeling water away from underneath the tyre. This helps build resistance to aquaplaning.

Tread lugs. This is the main element of the tread, with which many of the features are added or carved into. The lugs main purpose is to provide good traction.

Tread rib. Also occasionally known as transverse voids, these are circumferential ribs or contact bars that run around the tyre tread.

Tread groove. These are depressed parts of the tread, similar to sipes but often much longer and deeper. These grooves form a specific pattern, with shapes and sizes calculated to improve a tyre’s quality in key areas. Generally, these features serve to improve the tyre’s braking effectiveness and steerability. The depth of the grooves, as well as their pattern, can also prove decisive in the rolling noise level.

Dimples. Although not always present, dimples are often included to improve tyre cooling.

Tread voids. Similar to sipes, these voids create the space required to channel water from underneath the tyre when driving on wet surfaces. This maintains good traction, since the water is channelled through the wider voids along the axis

Similarly, the relationship between these void areas and the lug area influences the overall contact patch of a tyre. A larger number of voids, for instance, can diminish a tyre’s grip on dry surfaces, yet offers better performance on wet surfaces. As a result, the number of voids depends on the tyre’s purpose, as specific wet or ‘rain tyres’ may feature more tread voids.

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An overview of the basic tread elements.

Tread And Tyre Patterns

Now that you have a basic overview of the tyre tread features, it may also help to understand the basic patterns used in various tread designs. This is refers to how the ribs and lugs, in addition to any grooves and sipes, are lain out.
 
Depending on how this is done, a tyre can have very different parameters - this is why a winter tyre and summer tyre are often very different, for instance.

Rib pattern.
Parallel S-shaped voids along the axis.

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Rib pattern

Positive points:

  • Lower rolling resistance
  • Good directional stability
  • Good steering control (thanks to lateral resistance)
  • Suitable for sustaining high speeds (thanks to low heat generation)

Negative points:

  • Poor grip when accelerating or braking on wet roads
  • Flexing of the treads can cause excess stress, resulting in a tyre that is more susceptible to cracking.

Uses:
These tyres are generally designed for use on hard road surfaces, such as tarmac and concrete. They are often fitted to the wheels of trucks or buses responsible for direction, depending on if the vehicle uses a front wheel steering system or rear wheel steering system, naturally.

Lug shape.
This pattern refers to a series of grooves which are perpendicular to the tyre’s circumference.

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Lug shape

Positive points:

  • Improved traction
  • Excellent grip when braking and accelerating

Negative points:

  • Excess noise at high speeds
  • Not suitable for high speed driving due to additional rolling resistance

Uses:
Such tyres are generally designed for dirt roads, so may often be found in 4x4 tyres and other designs. Similarly, they can often be found on the rear wheels of trucks and buses, as well as on all-terrain and other specialised vehicles.

Mixed, rib-lug shape.
A mixed shape pattern is, as the name suggests, a combination of the two previous shapes. It can feature varying combinations of S-shaped voids along the axis, as well as perpendicular grooves.

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Mixed shape

Positive points:

  • The central rib provides good directional control
  • The shoulder lugs offer good braking & driving power

Negative points:

  • The mixed shape offers a more balanced performance, so it is not as good in key areas as more specialised designs, such as pure rib or lug patterns

Uses:
These tyres are good for both paved and dirt roads and can be found on a variety of trucks and buses.

Block shape.
A block shape pattern refers to designs with independent blocks along the tread, separated by a series of interconnected grooves.

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Block shape

Positive points:

  • Good steering and stability on both wet and snow-covered roads
  • Good water dispersal properties thanks to the numerous grooves

Negative points:

  • Low durability, depending on the size of the tread blocks

Uses:
The main benefit to these tyres is there ability to perform well on snow. This makes them highly useful as winter tyres, as well as all-season tyres for passenger cars.

Asymmetric shape.
An asymmetric tyre tread is very common in many commercial tyres and refers to tread patterns that differ on each side. Typically, bigger blocks are used on the outer side, while the internal blocks are smaller, while a series of grooves help disperse water outwards.

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Asymmetric shape.

Positive points:

  • Good for high speed cornering thanks to the big contact area
  • Reduced tread wear on the outside of the tyre
  • Improved stability when turning, thanks to the bigger blocks

Negative points:

  • Need to be positioned correctly, due to the different sides

Uses:
These tyres offer great performance even at high speeds, making them suitable for sporting vehicles and more aggressive driving styles. Naturally, they are commonly used as motorsport tyres.

Directional pattern.
Directional tyre treads are also another very common tyre design and involve a series of lateral grooves positioned at the same angle on both sides of the tyre. This creates a ‘direction’ of sorts as all grooves point forward.

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Directional pattern

Positive points:

  • Very good traction and braking
  • Good water dispersal for stability on wet roads
  • A good choice for fast driving styles

Negative points:

  • Due to their directional nature, these tyres need to be installed with the correct orientation.

Use:
Directional tyres have plenty of uses and are most commonly found in high speed passenger vehicles.

As you can see, there is a clearly a lot of work that goes into designing a great tyre and the details in the tread certainly amount for a lot. If you know how each factor contributes to the products effectiveness, you can readily identify what conditions a tyre is designed for.