A prototype summer tire developed by Nokian Tyres is said to have demonstrated 64% superior rolling resistance against a premium ‘eco’ tire in testing conducted by the Finnish tiremaker. 
In a test held on Mar. 9, a Toyota Prius was fitted with the prototype tires and also with Michelin Energy Saver tires (both the same dimensions and pressure) and rolled down a ramp in neutral gear in windless conditions. As Nokian explains, the distance the car rolled corresponds directly with the tires’ rolling resistance – the further the car rolls, the lower the rolling resistance. Nokian reports that the car managed to roll 129 meters when fitted with its prototype tire, while it stopped after 78.9 meters when fitted with Michelin tires.
“Our tire of the future nearly reaches the best EU fuel efficiency class A and consumes considerably less than the best passenger car tires of today, which are two classes worse and only get class C,” said Teppo Huovila, vice president of R&D with Nokian Tyres. “Nevertheless the prototype offers a normal level with all other features.”
In addition to safety features, tire product development will, in the coming years, focus more and more on lowering the rolling resistance. “Tire material development actively searches for new improving possibilities,” Huovila added. “Up and coming are, among others, the next generation silica compounds and steel belt structures. They emit less heat during the deformation of the tire and consequently lower the tyre’s rolling resistance. In 2015, the best passenger car tires will probably further decrease fuel consumption by 5% compared to the best of today’s tires without compromising on the current safety features.”
At the moment, states Nokian, the rolling resistance of the best passenger car tires corresponds to grade C of the EU new grading system, but the majority of today’s tires belong to grades G, F and E. In practice, moving from one grade to the next means a decrease in fuel consumption of approximately 2%-3%.
“The product development and manufacture of such a tire are very challenging processes. Very precise structures, smaller tolerances and the newest special materials are required. All features must be on a good level in the tire; as a responsible manufacturer, we can never focus on improving just one feature at the expense of others,” Huovila added. (Tyres & Accessories)
