New Sumitomo all-season tires synch with weather conditions

Tokyo – Sumitomo Rubber Industries (SRI) is introducing a series of advanced all-season tires, in which the rubber compounds are tailored to “synchronise with all road surfaces.”

Among the next-generation products is a new Dunlop all-season tire said to synchronise with all road surfaces including snow, said the Japanese group's 22 July announcement.

Called Synchro Weather, the tire will be released on 1 Oct in 40 sizes, with the total to be expanded to more than 100 sizes up to 22” sequentially.

The key feature is SRI's ‘active tread’ technology, which changes the properties of rubber itself according to road surface conditions in response to water and temperature.

As unveiled last October, active tread controls the “movement of the polymer [molecules], which is one of the factors that contribute to the softness of rubber.”

With the new technology, SRI said it is able to combine the performance of summer tires and studless tires in its new products.

This is achieved by incorporating two 'switches' in the rubber that respond to changes in road surface conditions, the tire maker explained.. 

For the 'water switch', some bonds between rubber polymer chains were replaced with ionic bonds that can be desorbed and detached with water from covalent bonds. 

Contact with water activates the 'water switch', thereby softening the rubber surface and improving grip performance on wet roads. 

On drying, the polymer chains recombine with each other, restoring the rigidity of the rubber and returning to the same performance as standard summer tires. 

In addition, a 'temperature switch' is introduced by replacing some of the grip components in the rubber with a material that functions even if it is separated from the polymer. 

At room temperature, therefore, the rubber has the same rigidity as standard summer tires, but at low temperatures, the 'temperature switch' activates to provide a softer grip on icy roads.

"At room temperature, it has the same rigidity as standard summer tires, but on icy roads at low temperatures, the rubber is as soft as standard studless tires," said the release.  

So, by combining the two switches, SRI claims to have created "an unprecedented rubber that delivers high performance on all road surfaces, including dry, wet, snowy and icy surfaces."

In addition to the 'snowflake mark' that can be driven under highway winter tire regulations, an 'ice grip symbol' shows the tires "have cleared" the standards for ice performance set by the UN regulations.