Something about bicycle frame

Bicycle frame is a main component of a bicycle. Wheels and other components are fitted on the bicycle frame. The modern and most common frame designed for an upright bicycle is based on the safety bicycle, which consists of two triangles, a main triangle and a paired rear triangle. This is known as the diamond frame. Besides the ubiquitous diamond frame, many different bicycle frame types have been developed for the bicycle, several of which are still in common use today.

In the diamond frame, the main "triangle" is not actually a triangle because it consists of four tubes: the head tube, top tube, down tube and seat tube. The rear triangle consists of the seat tube joined by paired chain stays and seat stays. Frame size is traditionally measured from the center of the bottom bracket to the center of the top tube. Typical "medium" sizes are 54 or 56 cm for a European men's racing bicycle or 46 cm for a men's mountain bicycle.

You can make a good bicycle frame out of any of the common metals, with any desired riding qualities, by selecting appropriate tubing diameters, wall thicknesses and frame geometry.