The specialized fatboy is our classic mountain bike slick tyre as it rolls smooth and fast to effectively transform your mountain bike for the road or trainer and with new sizes you39re now able to convert your 29er too specialized fatboy tyre features casing 60 tpi bead wire compound 70a flat protection flak jacket 26 x 125 max psi 100 approximate weight 390g 700 x 35mm psi 70 100 approximate weight 430g 700 x 45mm 29 x 17 psi 50 75 approximate wei