this is brilliant, new tire tech automatically deploys and retracts studs depending on temperature. The Hakkapeliitta 01 tire has a new temperature-sensitive compound that deploys and retracts studs

When the road surface is warm enough, the studs, which themselves have been redesigned specifically for this tire, sit back beneath the surface of the rubber. As the road surface gets colder—like, tire-in-contact-with-ice cold—they push out. Nokian says it’s been working on this technology since 2014, around the time it debuted a concept tire that deployed studs with the press of a button. Other startups had attempted to deliver such products, but they never arrived.

The key is what the company calls an “adaptive base compound.” This is the material that the studs sit in, and it’s sensitive to temperature—becoming rock-solid when cold, and softer and more pliable when warm.

https://www.thedrive.com/news/nokians-new-tire-has-studs-that-magically-retract-when-its-warm