For more than a century, bicycle designs have used single chain drive transmissions in the belief that no other option exists. An alternative to a chain driven system is an endless belt transmission system using all three distinct belt forms; flat, V, and toothed. In the described transmission the belt acts as a combination flat and V-belt on the drive pulley, and like a timing belt on the driven pulley. Uniquely, the belt teeth have an asymmetric, pawl like tooth profile. This permits safe operation in conditions when the driven pulley circumference is already moving faster than the drive belt teeth, a common occurrence during bicycle or scooter coasting. The material memory of the elastomeric belt acts to bias the drive to disengagement, yet the belt and drive pulley are light. Combined with carefully positioned back idlers, the mere initiation of a power stroke quickly engages the transmission automatically. One major application described here is a reciprocating drive actuated with natural leg action that is easily augmented with power assistance, producing a Human-Hybrid Powered Vehicle (H2PV). A model demonstrates significant weight reduction versus chain and sprocket drives, along with the elimination of an overrunning clutch or free-wheel, clean and quiet operation, weight efficient design, and use of modern lightweight materials like thermo-plastic plastics, glass, carbon or aramid fibers, and thermo-set plastics (polyurethanes).

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