Tue January 4 12:55 pm 2005 in category Product news


Nokian NRHi is a summer tyre in the H speed category manufactured using only purified, low aromatic oil. Persistent research and development efforts have enabled Nokian Tyres to become the first tyre manufacturer to offer an environmentally friendly tyre in the H performance category with excellent wet grip and other safety characteristics.

Nokian Tyres has been systematically studying and testing various options for replacing toxic oils with clean alternatives for about ten years. The manufacture of high-performance summer tyres without HA oils, classified as harmful, requires advanced chemical know-how.

The main markets of Nokian NRHi include the Nordic countries, Russia and Central Europe. Retail sales of the product began in spring 2004.

Safe and quiet also in wet weather

The greatest challenge in the development of the Nokian NRHi was to find a solution to the wet grip equation when leaving out the HA oils that are ideal for the chemical process. We achieved good wet grip properties by using new types of polymers and silica, as well as clean oils, in the mixture.

Nokian NRHi has efficient grip on wet roads and works flawlessly in all summer temperatures. Wet braking tests were conducted in both cool temperatures, less than 10 degrees, and high temperatures, more than 25 degrees. The test results were convincing. The wet grip improved by six per cent over its predecessor.

The tread pattern of the Nokian NRHi resembles a feather. The lateral grooves open to the sides, efficiently removing water from between the tyre and the road surface. The tyre is directional – that is, its direction of rotation is predefined. The green colour in the bottom of the longitudinal grooves indicates that the product is friendly to the environment.

The structure, tread pattern and rubber compound of the Nokian NRHi make for an easily rolling tyre, with a rolling resistance up to 7 per cent better than that of its predecessor, the Nokian NRH2.

Various solutions have been used to dampen the tyre’s noise. The distribution of the tread pattern block has been optimised and the structure has been revised. In addition, circumferential platforms have been designed in the bottom of the main grooves together with small cavities in the pattern blocks that are next to the grooves. These solutions break the high-frequency noise that is created when driving on a smooth surface with straight grooves (known as the organ pipe effect).

The drive-by noise and inside noise is low and its tone is agreeable. The level of drive-by noise from the Nokian NRHi in decibels is clearly less than the limit stated in the EU directive that entered into force at the beginning of August 2003.

The Nokian NRHi keeps steady direction and is long-lasting. The tyre touches the road with precision and softness, thanks to which braking performance improves and the tyre wears evenly. The symmetrical shoulder parts of the tread pattern improve the excellent cornering properties.

The info field gives the inflation pressure recommendations

The bead area of the Nokian NRHi has been renewed. A sealing ring was added to the rib that shields the rim. The design protects the sensitive rim from sand, dirt and impurities.

The bead area of the tyre contains an info field, which facilitates servicing and increases driving comfort. The info field contains a row of recommended tyre pressures. The tyre fitter marks the correct inflation pressure in the info field. When checking the tyre pressures, the driver can ensure the correct value by checking the recommended pressure in the info field.

The tyre location can be marked in the diagram next to the pressure markings. The marks function as a location reminder during seasonal storage, which facilitates the rotation of tyres from one axle to another and extends their service life.

Sufficient tread depth – about 4 mm – efficiently prevents the risk of aquaplaning. The Nokian NRHi also includes a tread wear indicator familiar from other products, clearly indicating the remaining tread depth in the main grooves in millimetres. The driver can easily take care of his or her safety by driving with tyres that are in a good condition.

Additional information from Nokian Tyres plc:
Teppo Huovila, Product Development Manager, phone +358 3 340 7701,
e-mail: [email protected]