Cheng Shin C638 Raised Center Bicycle Tire (Wire Bead, 26" x 1-3/8", Black Wall) Measures 26 x 1-3/8-Inch Includes a wire bead Comes with a black wall ISO diameter 590mm Note: This is NOT the same diameter as a decimal tire size, such as 26" x 1.25, or a Schwinn S-6 1 3/8" tire