Vertically adjustable bicycle assembly

A bicycle including an adjustable assembly, the adjustable assembly comprising:

• a first tubular support configured to attach to one of a bicycle frame and a bicycle saddle, the first support having an interior surface;
• and
• a second tubular support configured to attach to another of a bicycle frame and a bicycle saddle, the second support slidably positioned longitudinally within the first support, said second support being adjacent at least a portion of the interior surface of the first support, the second support comprising a radially flexible movable portion disposed proximate a lower end thereof, wherein said movable portion is radially expandable relative to a longitudinal axis of the second support between a radially expanded position and a radially retracted position, and wherein an outer surface of said movable portion engages at least a portion of the interior surface of the first support when the movable portion is in the radially expanded position, and wherein when said outer surface of said expansion portion is moved to the radially retracted position, the first support is longitudinally movable relative to the second support;
• a retention assembly coupled to the second support, said retention assembly being longitudinally movable between a locked position, in which the retention assembly is at least partially within an interior space of the movable portion and blocks the movable portion from moving to the radially retracted position, and an unlocked position, in which the movable portion may selectively move to the radially retracted position;
• and
• an actuator operatively coupled to the retention assembly, whereby movement of the actuator moves the retention assembly between the locked and unlocked positions;
• wherein a resilient member coupled to the retention assembly biases the retention assembly downwardly such that the retention assembly is normally biased into the locked position, and wherein an upward motion on the actuator raises the retention assembly against the downwardly directed bias;
• a biasing assembly operatively coupled within the first support, said biasing assembly biasing the one of the first support and the second support relative to one another to selectively raise an elevation of the bicycle saddle when the movable portion is in the radially retracted position;
• wherein the biasing assembly is exerts an upwardly directed force in a direction generally opposite of the downwardly directed bias of the resilient member of the retention assembly;
• and
• wherein the adjustable assembly is configured for placement within a seat tube of a bicycle.