We view speed and control as a right, not a privilege, which is why we took the tread design of the Fast Trak Sport tire a step further by manipulating each knob with Finite Element Analysis. Paired with extensive rider feedback and design experience, the result is an XC tire with less rolling resistance, more traction, and a rugged casing that's ready for anything. Specialzied Fast Trak Sport Tyre Features Casing: 60 TPI Bead: Wire Compound: 60a 26 x 2.1, psi 25-50 27.5 x 2.1, psi 25-50 29 x 2.1, psi 25-50 29 x 2.3, psi 25-50