Asymmetric tires (Asymmetric tyres)

Asymmetric tires combine two different tread types. At first glance, the tread shape of the right and left tires is different, as if the manufacturer had combined the symmetrical and directional tires together. Typically, tires with an asymmetric tread pattern boast the best performance. This is because their construction allows the tread to be split into two completely different parts. The first stiff part for better handling and longer tire life, and the second part aimed at reducing noise and sufficiently draining water from the track.

The asymmetric tire construction is designed to give the best possible performance on both dry and wet roads. For this reason, it has a split tread pattern between the outer and inner halves (considered in relation to the position on the vehicle). The outer half is designed with the aim of good tire handling, so it contains fewer cuts and, in turn, as many robust blocks of rubber as possible. The inner side of the tread, on the other hand, provides good straight-line traction and tries to prevent aquaplaning by means of angled sipes that channel water or snow slush away from the track under the tire.

History of asymmetric tires:

Asymmetric tires are the youngest in design, but also the most complex, compared to both symmetric and directional tires. The first tire with an asymmetric tread pattern was introduced by Michelin in 1965 – the Michelin XAS. This asymmetric tire was specifically developed because of the requirement to improve the directional stability of the now legendary Citroën DS. It also became the first production tire to be suitable for speeds of up to 210 km/h, an impressive figure for the time. Thanks to its high performance, it was used from 1968 onwards for Formula France races, circuit racing and rallying.

Despite these undisputed and legendary achievements of the asymmetric tire, it is only recently that this type of tread has come to the fore. This was primarily due to their high purchase price. With the advent of advanced manufacturing technologies and the availability of computer simulations needed to design asymmetric tread patterns, asymmetric tires are gradually becoming more affordable and common.

Modern asymmetric tires can even be made from several types of interconnected rubber compounds. They are therefore asymmetrical not only in shape but also in material!

The more demanding production of asymmetric tires is particularly reflected in their higher purchase price. However, the excellent handling characteristics of asymmetric tires are worth the higher price. You will find them especially on more luxurious vehicles with powerful engines and, of course, on sports cars. From size R18 onwards, asymmetric treads are practically the only choice.

Asymmetric tyres are also said to be less noisy and achieve a longer mileage life.

Advantages of asymmetric tires:

shorter braking distance on dry and wet roads
longer service life
lower fuel consumption
better handling and grip
lower noise level due to the half-arrow shape of the tread blocks

Disadvantages of asymmetric tires:

higher purchase price
mounting – outer and inner side are different

How do I know an asymmetric tire?

On the side of an asymmetric tire you will find the inscriptions OUTSIDE / INSIDE or IN/OUT. You can also recognise asymmetric tires by the shape of the tread. When you look at the tread pattern head-on, you will notice that the right and left halves of the tread are different – asymmetrical.

Fitting an asymmetric tire:

When mounting the tire on the rim, particular care must be taken to ensure that the position of the inner and outer sides are maintained. The initial correct position on the rim is important, then the outer side is always the outer side, no matter where you mount it on the vehicle. Asymmetric tires do not differentiate between left and right. There is only one shape! When mounting a significantly asymmetrical tire, it does look like one side is mounted backwards from the front view, but that’s okay. On a properly shod vehicle, the driver should only see the word OUTSIDE.

In exceptional cases of emergency, an incorrectly fitted asymmetric tire may be used for a short time. However, it is important to bear in mind that a tire fitted the wrong way round does not have the same adhesion characteristics and to rotate or replace it at the earliest opportunity.