BICYCLE FRAME HAVING A MODIFIABLE STRUCTURE

摘要

The frame has a saddle tube (3) and a steering head (6) receiving a front fork (7) connected by a frame top tube (8). The bottom ends of the saddle tube and front down tube (2) are removably inserted and lockable in a crank axle block (1) which carries the pedals (11,12). The front down tube and the top tube can have their front ends pivotally connected to the steering head.