Oh? How do those work? Obviously they're physically possible (you could fill a tire with Utility Fog) but I didn't realize they were yet technically feasible.
Although they still have the issue outlined in http://www.livestrong.com/article/222689-airless-bicycle-tir... (on the subject of the previous airless generation, using flexible foam instead of rubber fill): shocks can't be spread around as they are in pneumatic tires (where the tire gets overpressured all around and most of the shock's energy is spread around the tire unless it's so big it reaches — and damages — the wheel's rim)
