Bicycle seatpost assembly

A bicycle seatpost assembly comprising:

• a first cylinder;
• a second cylinder configured to be telescopically received in the first cylinder;
• a mounting structure attached to a distal end part of the second cylinder, the mounting structure being configured to fixedly mount a bicycle saddle to the distal end part of the second cylinder, the mounting structure including:
• an attachment member;
• a mounting member having a mounting surface on which the attachment member is mounted;
• and
• a clamping member configured to clamp the bicycle saddle between the clamping member and the attachment member;
• a first engagement portion provided to an outer periphery of the second cylinder;
• and
• a second engagement portion that is integrally attached to the clamping member and that is configured to engage with the first engagement portion such that a circumferential position of the mounting structure relative to the second cylinder is selectively adjustable, wherein
• the second cylinder is telescopically movable relative to the first cylinder in an axial direction,
• one of the first engagement portion and the second engagement portion includes recesses, each of the recesses having a bottom extending in the axial direction,
• the other of the first engagement portion and the second engagement portion includes a projection configured to be selectively provided in one of the recesses to position the mounting structure relative to the second cylinder at one of circumferential positions,
• the clamping member is configured to be movable relative to the mounting member in the axial direction,
• the clamping member is configured to be rotatable together with the mounting member relative to the second cylinder in a circumferential direction of the second cylinder, and
• the mounting member and the clamping member are separate members.