Stans No Tubes CREST MK3 27.5 Aluminum Rim Black 32HWider and even lower profile, the Crest MK3 sheds weight for faster acceleration and climbing. The new rim shape adds strength and virtually eliminates the chance of a pinch flat. Bead Socket Technology (BST) secures the bead of the tire creating an air tight seal while allowing the the tire's sidewall to expand to it's true, rounder and more effective profile. The result is better traction and lower rolling resistance WideRight optimized for tires 2.