Lightened tie rod with stepped pivot

The rod (1) has a pivot rod (2) that is arranged with a head section (3) on which an upstream articulation unit (4) such as kneecap sphere, is arranged. The pivot rod is arranged such that the head section presents a progressive decrease (10) of its cross-section in an upstream direction and downstream of a directing axis (X-X'). A surface of the cross-section of the pivot rod or gauge section (SJ) is located upstream of a gauge plane (PJ), and is higher or equal to a surface of a set of cross-sections (S1-S4) located downstream of the gauge plane. An independent claim is also included for a steering system.