an integrated and self - contained suspension assembly having a gas spring integrated with a shock absorber is described . the rigid gas cylinder of the air spring is divided into a first gas chamber and a second gas chamber . a flow port connects the first and second gas chambers , and can be manually opened or closed by valve and a simple one - quarter turn rotation of an external knob to instantly switch the gas spring between two different spring rates . the different spring rates are functions of the separate or combined volumes of the two . gas chambers . the integrated suspension assembly is compactly packaged and self - contained , i . e ., does not require any externalities , such as gas sources or electricity , to operate .