Abstract: Disclosed is an apparatus for varying eccentrically or centrically the shaft of the bicycle wheel in order that the bicycle can run up and down like horseback riding beside regular level riding. The apparatus has an eccentric hub including a shaft housing formed integrally in eccentric position between two hub discs having an opening and a shaft penetrated through said shaft housing, two circular supporting plates coupled rigidly each other by three connecting rods to reserve revolvably said eccentric hub therebetween, each which has a hub disc housing formed in its eccentric position said hub disc housing has a relatively large hole on its centric portion to exposure the shaft and also a plurality of openings corresponding to different eccentric positions on its circumference of circle, and a resettable spring loaded rod for locking the eccentric hub between the hub disc housings of the circular supporting plates by passing through the openings in alignment with each other.

Abstract: Disclosed is an apparatus for varying eccentrically or centrically the shaft of the bicycle wheel in order that the bicycle can run up and down wavy manner like horseback riding beside regular level riding. The apparatus has an eccentric hub including a shaft housing formed integrally in eccentric position between two hub discs having a plurality of notches corresponding to different eccentricities of the shaft and a shaft penetrated through said shaft housing, two circular supporting plates having a slot for locking and two cover plates so that each hub discs of the eccentric hub is rotatively mounted relatively between each hub disc housings of the circular supporting plates and each cover plates and can be rotated to adjust the eccentricity of the shaft, and a locking means fixed on said circular supporting plate for setting the hub disc in the selected eccentricity of the shaft by matching it with any one of the notches through the slot.