Abstract: A spike cluster adapted for attachment to the bottom of an athletic shoe includes a body having a concavity in its upper face with a rim at the periphery of the upper face surrounding the concavity. Means are provided on the upper face of the body for attachment thereof to the bottom of a shoe. A plurality of spikes are located near the periphery of the lower face of the body and extend downwardly therefrom. Each spike has a vertical bore therein, open at the bottom and acting to provide improved traction, particularly on wet surfaces. A protrusion on the lower face within the area bounded by the spikes also extends below the lower face. The cluster may be secured to the bottom of an athletic shoe with the rim providing a clamping surface around the upper margin of the cluster for frictional engagement with the bottom of the shoe. Thus, movement of the cluster relative to the shoe under the stress of use is resisted. The protrusion acts as a shedder to prevent accumulation of dirt between the spikes.