A supplemental sole is adapted to be secured to a sole of a shoe for releasable coupling to a cylindrical pedal of a bicycle. An operational assembly formed in the supplemental sole includes a housing with a forwardly facing chamber. A sleeve is within the forwardly facing chamber. A primary lever pivotally coupled to the housing has a forward region movable between a lowered release orientation beneath the chamber and a raised locked orientation securing the sleeve within the forwardly facing chamber. A trigger is axially reciprocable within the housing. The trigger has a forward end located in the chamber when in the release orientation. The forward end is located rearwardly of the chamber when slid rearwardly by the pedal for raising the primary lever to the locked orientation.