Bending.

References

Cavalerie
B'TWIN

The bending process is a mechanical deformation of the tube, defined by a selected radius and angle. This is the first phase of forming the tubes. It is often used to provide the required clearance for wide tires on rear triangles (chain stays and seat stays). This is a low-cost method suited for simple shapes, but still requires great precision. MILC Ind. offers a particularly high standard in this field.