subject: Nokians Unique Slush Planing Tests [print this page] Slush means danger and is a frequent situation. Slush planing is imminent because the tyre (In Finnish: rengas) loses contact with the road and you cannot steer the car anymore. On slush the risk of fatal accidents is 4.9 times higher than on dry roads, a study of Tampere University of Technology proves.
You have to change lanes to overtake others and you have to cross the slush barrier between the lanes. Then the driver turns right again and again crosses the slush barrier. Here the car loses side grip and can easily skid.
As the pioneer of slush tests Nokian Tyres has carried out slush planing tests for 15 years and owns as the one tyre manufacturer a unique proving ground for slush planing tests longitudinal as well as lateral, knows Matti Morri, the Technical Customer Service Manager from Nokian Tyres. The Nokian engineers have developed exact test methods for slush planing testing. Although Nokian is already the forerunner of the branch and can improve their tyres more and more every year. During recent years e.g. several German car magazines have included slush planing tests in their winter tyre test programs for the first time.
Slush planing is more dangerous than aquaplaning
Slush planing makes tyres lose contact with the ground with much lower speeds than aquaplaning: Already at speeds below 50 km/h tyres may lose contact with the ground on slush whereas aquaplaning typically occurs with speeds up from 80 km/h on standard test arrangements at Nokians tests track. This is alarming. Without tyre contact to the ground the car cannot be steered anymore and the braking distance becomes much too long.
Slush planing is more dangerous than aquaplaning for the following reasons: On ordinary roads the depths of the layer of water is rarely more than 10 millimeters but slush can be much thicker namely up to 40 millimeters on the driving lanes and up to 100 millimeters between the driving lanes. Slush has got a higher viscosity than water, therefore is pastier, and cannot be led off in the tyre tread channels as easily as water.
