A wheel, preferably adaptable for use with a skate, is provided having a semi-permanent stiffness-modulating insert. The wheel comprises a toroidal wheel component having a hollow toroidal core which can be filled with a stiffness-modulating material. The wheel is split along a line from the inner circumference of the toroidal wheel component to the inner circumference of the core so as to allow for insertion of the stiffness-modulating material. The toroidal wheel component is preferably molded with the split edges slightly spaced apart from each other. In use the edges are held together in abutment with each other or with a toroidal spacer placed between them, preferably by wheel hubs engaging with each other and with the toroidal wheel component of the wheel.