A bike frame is the main component of a bicycle, onto which wheels
and other components are fitted. The modern and most common frame design for an upright bicycle is the diamond frame. The diamond frame is made of two triangles: a main triangle and a paired rear triangle.
The main triangle consists of the head tube, top tube, down tube and seat tube. The rear triangle consists of the seat tube, and paired chain stays and seat stays.
The head tube contains the headset,
which interfaces with the fork. The top tube connects the head tube to the seat tube at the top, and the down tube connects the head tube to the bottom bracket
The rear triangle connects to the rear dropouts,
where the rear wheel
is attached. It consists of the seat tube and paired chain stays and seat stays.
The chain stays run parallel to the chain, connecting the bottom bracket
to the rear dropouts.
The seat stays
connect the top of the seat tube to the rear dropouts.Full Article