The weather was warm and dry for our afternoon track session. The Circuit de Nevers is a very fast, flowing racetrack with a thrilling, Parabolica-like bowl that leaves you on the edges of your tires for a long time. Compared to the Rossos, the Rosso IIs feature a wider center rib and revised shoulders with a larger slick area and a stickier compound. We rode everything from a Ducati 848 to a Honda CBR1000RR, but learned the most aboard a Yamaha YZF-R1. Its muscular yet easy-to-manage Crossplane engine highlighted the exceptionally predictable behavior at the limit—spinning without sliding—that makes the Rosso IIs so confidence-inspiring. And although they’re advertised as street tires, on-track durability impressed. A final, 25-lap endurance session on the rubber-munching BMW S1000RR revealed no appreciable degradation in grip or excessive wear.