Spike Race 33 RimBead-Bite ridges add friction to the bead/rim interface to decrease tire burping. The Oohbah profile acts like corrugated steel to the prevent folding rims and adds rigidity for sharper handling. Due to the Oohbah profile, which is convex, Spank/Fratelli Industries tubeless tape is recommended as it holds that contour better than many other tubeless tape . Dynamal alloy used in the extrusion has high tensile strength and yield without affecting fatigue life. The Manufacturer Spec ERD specification listed uses the less common “ERD+” method. ERD+ is the manufacturer listed diameter of the rim at the spoke nipple seat and does not account for the height of the spoke nipple shoulder when calculating spoke length. If unfamiliar with this system of measurement physically.