Hakkapeliitta 8 SUV

A tyre blogger interviewed our technical customer service manager, Matti Morri, to discuss the new Hakkapeliitta 8 SUV tyres.

What are the new properties with the Hakkapeliitta 8 SUV?

The Hakkapeliitta 8 SUV has quite a few new properties. It was exactly a year ago that we launched the Hakkapeliitta 8. Since then, the model has won top marks in more than a dozen tyre tests. The new tyre’s surface model was developed further, giving the Hakkapeliitta 8 SUV a new and slightly different approach to the surface. The stud principle is similar to that of the Hakkapeliitta 8, so the Hakkapeliitta 8 SUV tyre has about 50% more studs than the Hakkapeliitta 7 SUV model. Clearly, the Nokian tyre models have many more studs than any competitor’s tyres.

The stud used in the Hakkapeliitta 8 SUV is a new type of anchor stud. Studs in SUV tyres are usually somewhat bigger than those for passenger cars, the sizes being 11 mm and 10 mm, respectively. Another difference is that the stud has a new flange, with the same principle applied in the Hakkapeliitta 8: the stud has a so-called damping pocket below the flange, which cushions the contact with the road and creates a more comfortable noise level inside the vehicle.

The Hakkapeliitta 8 SUV tyre also has a new material mixture for the side surface. Why?

Nokian Tyres have had the ʻHakka-turvaʼ insurance available on the domestic market for many years now. Under this insurance, the company will replace a tyre at no charge if it is damaged accidentally during the first year, provided that the remaining tread depth is at least 4 mm. None of our competitors provide this kind of unique service. We started to investigate the damage covered by the Hakka-turva insurance. We noticed that tread damage such as punctures can often be fixed whereas damage to the side surface usually means that the tyre cannot be repaired. Damage to the side is especially common in Russia, because of the bad condition of roads and high driving speeds.

This encouraged us to develop an endurance test for the side surface. We created a barrier 120 mm high on the test track and oriented it at a suitable angle toward the driving direction. Then we drove against it at various speeds and studied the effect on the tyre. In the collisions, the side of the tyre hits the rim flange and flattens. This cuts the tyre cords and makes a hole in the tyre’s side surface. To improve the strength of the side surface, we developed an entirely new mixture for the side of the Hakkapeliitta 8 SUV model. Aramid staple fibres were used as a binder and a reinforcing material in the mixture. Aramid is commonly used in, for example, the aircraft industry and defence industry. The aramid fibre is cut to very small lengths, and this staple fibre is then mixed into the rubber compound for the tyre side surfaces. The fibre improves the tear-resistance and toughness of the compound and very effectively prevents various types of damage to the side surface.

What is the reason behind the larger number of studs in Nokian winter tyres?

A new decree on studded tyres took effect in Finland and Sweden in July of last year. Under that decree, the maximum number of studs per rolling metre is 50 in passenger cars. This means that the number of studs had to be reduced. But the law also stipulates that the number of studs may be higher if the tyre manufacturer can verify with an over-run test that the road-wearing influence of the tyre with a higher number of studs is lower than the limit set by the law. By working day and night and performing these tests, we proved that the road-wear effect with a higher number of the new type of studs was clearly lower than the maximum permissible under the law.

The over-run tests were practically implemented in such a way that a plate of rock material meeting precise specifications was driven over 400 times with the test tyre. The plate was weighed before and after the test. This provided the information needed on the tyre’s influence on road wear. This is the official test method specified by law. Our competitors have chosen the easier way and merely reduced the number of studs. A higher number of studs, of course, significantly improves both longitudinal and lateral grip on a slippery surface.

New properties with the Hakkapeliitta 8 SUV:

  • A new composition for the side surfaces
  • 50% more studs
  • A new anchor stud, which reduces the road wear and dampens noise in the cabin

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