Schwalbe Stelvio tires are used by road racers around the world and they have been independently tested as the fastest 20" tires in the world. The Stelvio features a DualCompound casing: the exceptionally supple casing is astonishingly light and delivers exceptional road feel. The center tread features Schwalbe's Qualifier Compound, a special racing compound that has been optimized for low rolling resistance. The side tread is made from sticky, low-durometer Silica rubber for superior grip while cornering. A RaceGuard Belt provides puncture protection: it consists of two carcass layers, between which is sandwiched a virtually impenetrable rubber compound. The rubber mixture is made from a special rubber that is very flexible and actually reduces rolling resistance. We also specified a folding Kevlar bead to further reduce weight. And as a final finishing touch, Schwalbe specially matched the mango/black casing to the paint of our Speed Pro. 120 psi. 185 grams.