The present invention relates to a
kingpin (1) for a semitrailer of a semi-trailer vehicle, which extends substantially along a longitudinal axis (X), with at least one wear detection means arranged in the
kingpin (1) perpendicular to the longitudinal axis (X) such that wear of the
kingpin (1) perpendicular to the longitudinal axis (X) can be detected optically and / or by sensors. The kingpin (1) is characterized in that the wear detection means comprises: • at least one wear element (11c, 12c) which is arranged in and / or on the kingpin (1) perpendicular to the longitudinal axis (X) such that wear of the kingpin (1) perpendicular to the longitudinal axis (X) equally wears the wear element (11c; 12c), wherein the wear element (11c, 12c) is arranged in the circumferential direction (U) at least partially, preferably completely, around the kingpin (1) • at least one cavity (11a, 11b, 12a, 12b, 14c) which extends in the circumferential direction (U) corresponding to the wear element (11c, 12c), wherein the cavity (11a, 11b, 12a, 12b, 14c) is closed fluid-tight by the wear element (11c, 12c), preferably perpendicular to the longitudinal axis (X), wherein the cavity (11a, 11b, 12a, 12b, 14c) contains a fluid at
overpressure, and • at least one
pressure sensor (16) which is designed to detect the pressure of the fluid in the cavity (11a, 11b, 12a, 12b, 14c), wherein the wear element (11c, 12c) is dimensioned perpendicular to the longitudinal axis (X) in such a way that the fluid can escape through a through-opening of the wear element (11c, 12c) created due to wear when a wear limit of the kingpin (1) is reached at this point on the kingpin (1).