Over the years, tyre manufacturers have developed hundreds of tyres. Tread, rubber compound, tread pattern … a tyre is made up of several different components, and each one is unique. However, based on the tread design, 3 main types of tyres can be identified: Symmetric, asymmetric and directional. What is the difference between these 3 types of tyres?
A tyre with a symmetric tread is designed for low powered cars that do not place high loads on their ground linkage. This is the reason why this tread is mainly reserved for small tyre sizes. Compared with an asymmetric tyre, the tread is characterised by an identical inner and outer tread pattern. In general, the symmetric tyre is less technical than the other two treads patterns and has no rotational or fitting direction.
A few years ago, this type of tread was omnipresent in the sports scene, driven by emblematic products such as the Goodyear GS-D3. Directional tyres efficiently clear water to significantly reduce the risk of aquaplaning. They also offer good traction. Compared with an asymmetric tyre, they are usually noisier and are not as versatile since the balance of performance is less uniform. This type of tread is strongly represented in winter tyre ranges since the tread design is perfectly adapted to winter conditions where snow traction is required. When fitting this type of tyre, it is important to follow the direction of rotation shown by an arrow engraved on the tyre’s sidewall. (See the diagram).
The asymmetric tread is a must in the field of sporty road tyres. Created in 1965 with the Michelin XAS, the asymmetric tread has progressively become a fixture eclipsing the directional tread in the sports tyre category. Asymmetric tyres are easy to identify since their inner and outer sidewall have a different tread design and offer different characteristics. For example, on a Michelin Pilot Sport Cup the inner part of the tyre is optimised to drain water. The outer part of the tyre, mostly required when cornering, has a typically “dry” design to promote grip. With the aim of producing a versatile product, note that some asymmetric tyres even use a different rubber compound for the inner and outer tread allowing the compound to work at its optimal best. Most drivers do not understand how to fit asymmetric tyres since they are subject to a rotational direction and not a fitting direction. This means that, on the left and right side of the vehicle, the treads do not point in the same direction. Nevertheless, the tyre’s performance and ability to clear water is not compromised. For example, the left tyre will mostly clear water towards the rear whereas the right tyre will clear water towards the front (See the following diagram). The sidewall stamped ‘inside’ must be facing towards the inside of the vehicle and the sidewall stamped ‘outside’ must be facing outwards.