Abstract: The present invention is directed to an improved variable sprocket transmission of a type that is particularly well-suited for use in multi-speed bicycles. More particularly, a variable sprocket transmission for a multi-speed bicycle is provided which can be smoothly and easily shifted without noise, is reliable, and can be easily used by both experienced and novice bicyclists. The variable sprocket transmission of the present invention can be manually shifted through a sequentially ordered set of distinct speed ratios using a single shift lever or, in the alternative, can be automatically shifted without input from the bicycle rider based on measured operating parameters.