Multistage sprocket assembly for a bicycle

A sprocket assembly for a bicycle comprising at least one larger diameter sprocket having a plurality of teeth of an equal distance formed on an outer periphery thereof, at least one smaller diameter sprocket rotated in concert with said larger diameter sprocket and having a plurality of teeth of an equal distance formed on an outer periphery thereof, a driving chain meshing with said plurality of teeth of said smaller diameter sprocket and being able to shift from a first center of a space defined between the teeth of one pair of adjacent teeth located at the smaller diameter sprocket to a second center of a space defined between the teeth of one pair of adjacent teeth located at the larger diameter sprocket, a distance between said first and second centers being not equal to an integer multiple of the pitch of said driving chain such that said driving chain is bent between said first and second centers and is deflected from a moving direction thereof which is along a tangent line drawn from said first center of said smaller diameter sprocket, and such that a deflection point is provided on said driving chain between said first and second centers so that a first line passing through said first center and said deflection point, and a second line passing through said first center and said second center will intersect with an included angle formed therebetween.