Airless—or non-pneumatic tires—have popped up from time to time over the past few years, and while they offer many advantages over traditional air-filled tires, they haven’t been available outside of research labs—until now. Polaris is officially the first company to offer a vehicle with non-pneumatic tires on its new Sportsman WV850 H.O. all-terrain vehicle. Military enthusiasts might recognize the ATV’s …