220g Superlight carbon rim T20mm is the lightest one in the market!! November 03,2016 18:29:24 220g Superlight carbon rim T20mm is the lightest one in the market!! X-Bike is producing superlight 220g tubular 20mm rim now,it is also with U-Shape 23mm width.The big advantage as : Stiffness Our superlight rims are made with what we consider the optimum blend of high strength and high modulus carbon fiber sourced directly from Toray in Japan. Stiff wheels improve tracking and maximize power transfer, both of which will make your riding faster and more fun. Our composite rims are exceptionally stiff! Wide Wider rims are better, as shown by both scientific and anecdotal evidence. Our XC race rims have an internal bead width of 24mm and AM (all mountain) mtb rims have internal widths of 26mm. Wider rims increase the volume of the tire, allowing you to run lower pressure and obtain more grip with lower rolling resistance.