Apparently it operates using two air chambers. One is to contain the regular tire air, the other is for pressurizing the studs and forcing them out. The secondary chamber is pressurized using air from the main chamber. When the studs are retracted the air in that second chamber is released to the atmosphere. The company claims this can be done 20 to 30 times before the main chamber needs have air added. The idea behind using these all-weather tires is to eliminate the need for having two sets of tires and wheels, and not having to fiddle with changing them.
The significance of this is not just the retractable studs but that these tires can actively change shape and alter their traction characteristics. Think of what the implications are for traction and handling in the future.
What we’re seeing here is the potential for active tires in the future offering levels of control well beyond what has so far been attained. Very cool indeed.