Abstract: A racing plate horseshoe system with movable calks has an arcuate racing plate attachable to a horse's hoof. An elongated groove is provided in the lower surface and has a plurality of spaced-apart threaded holes extending from the upper surface to the groove in the lower surface. The threaded holes are provided with set screws to protect the holes during fitting the shoes. One or more screw-attached calks are mounted to the racing plate, each calk having upstanding tabs engaged into the groove and having a depending blade. The blade calk is attached to the racing plate with a screw replacing the set screw. Each calk may be mounted to the racing plate in with blade in any one of four orthogonal positions with one or more of the upstanding tabs engaged into the groove of the shoe. A preferred embodiment uses cap screws installed in the threaded hole to provide simple wear-resistant calks.