Cobalt-free tyre studs reduce particle emissions

Cobalt has long been used in tyre studs due to its hardness, enabling grip in icy conditions as well as providing durability. But according to the researchers, cobalt is so tough that it chews up road surfaces and creates large amounts of airborne particle emissions. 

The study, published in Tribology International, saw alternative stud material containing iron-nickel tested on an asphalt surface. Compared to traditional studs containing cobalt, the new studs produced 20 per cent less wear and particle emissions, while still maintaining good grip on ice and packed snow.

“Cobalt is a cheap solution,” said Ulf Olofsson, a professor in the Department of Engineering Design at KTH Royal Institute of Technology. “It’s so hard that it doesn’t wear down, which is why it’s also mass produced for rock drilling tools.

“But asphalt is soft enough that cobalt-containing studs grind and pulverise it into ultra-fine particles that go deep down into the body when inhaled.”