Longboard and skateboard wheels are made of polyurethane. The diameter, hardness, core position, lip shape and color can be selected depending on the application and your riding style. The degree of hardness of a wheel is determined by a durometer type a and ranges from 73a to 101a. The smaller the value before the "a" the softer the wheel. The classic longboard wheel for cruising and carving has a soft duro between 75a and 83a and a diameter of 70mm and usually a "offset" or "sideset" positioned wheel core.
