An omni-directional wheel has a rim for mounting a tire, a hub for rotatably attaching the wheel to a vehicle, and a means for connecting the rim and the hub. The rim of the wheel has a part which is rotatably connected to the hub and which, when radially rotating around the hub, engages the surface of the tire mounted on the rim for rolling the tire on the rim. Thus, when the wheel is engaging the ground, the tire rolling on the rim causes a side movement of the wheel in a plan orthogonal to the normal plan of rotation of the wheel when attached to the vehicle. A solid-core tire for use with the omni-directional wheel has treads patterns or a helical coil shape for engaging the rotatable part of the rim. A method for manufacturing a solid-core tire is also provided.