Abstract: A bicycle seat suspension includes a parallelogram linkage having one end mounted to a seat post and another end supporting a saddle. A resilient member between opposed members of the parallelogram linkage deforms during linkage displacement to absorb shocks and to provide a restoring force to the linkage. An adjustment mechanism adjusts the initial preload on the resilient member to adapt the suspension system to varying terrain and riding conditions. The resilient member is also configured to provide varying restoring forces at varying degrees of compression to further adapt the suspension to varying riding conditions. The various members of the parallelogram linkage are configured for strength, light weight and manufacturing economy. A universal sleeve and shim arrangement is provided for adapting the seat suspension for use with bicycles having frames formed of tubing of different diameters.