Abstract: A bicycle seat tube assembly includes an arced component, a bottom bracket positioned below the arced component, and a seat tube including a pivot attachment at a lower end of the seat tube. The arced component includes a lower curved surface with a plurality of holes. The pivot attachment is coupled to the bottom bracket so that the arced component is pivotable relative to the seat tube about the bottom bracket, resulting in multiple seat tube positions between a fully forward position and a fully back position. A locking mechanism is configured to selectively lock the seat tube to the arced component. The locking mechanism includes a lock ring with a plurality of lock pins and a spring that pushes the lock ring towards the arced component. The lock ring and the spring surround the seat tube The lock ring is movable between a locked position and an unlocked position.

Abstract: A bicycle seat tube assembly includes an arced component, a bottom bracket positioned below the arced component, and a seat tube including a pivot attachment at a lower end of the seat tube. The arced component includes a lower curved surface with a plurality of holes. The pivot attachment is coupled to the bottom bracket so that the arced component is pivotable relative to the seat tube about the bottom bracket, resulting in multiple seat tube positions between a fully forward position and a fully back position. A locking mechanism is configured to selectively lock the seat tube to the arced component. The locking mechanism includes a lock ring with a plurality of lock pins and a spring that pushes the lock ring towards the arced component. The lock ring and the spring surround the seat tube The lock ring is movable between a locked position and an unlocked position.