A window lifter assembly for a window lifter provided for the adjustment of a window pane, comprising - a carrier, - a flexible traction means (Z, Z') for the transmission of an adjusting force for the adjustment of the window pane, and - a deflection piece that is non-rotatably arranged on the carrier and includes a guide channel for the deflection of the traction means (Z, Z') in a guide plane (xz-plane), wherein - the deflection piece is made of a polyaryl ether plastic and - for holding the traction means (Z, Z') in the guide channel at least one securing element (2A, 2B) on the carrier and at least one securing portion (11A, 11B; 35A, 35B; 50) are provided, wherein - the at least one securing element (2A, 2B) extends in a spatial direction (-y) that is substantially perpendicular to the guide plane (xz-plane) and faces the guide channel of the deflection piece, - the at least one securing portion (11A, 11B; 35A, 35B; 50) protrudes from an edge of the guide channel in a spatial direction (-z) that extends substantially parallel to the guide plane (xz-plane), and - the at least one securing element (2A, 2B) and the at least one securing portion (11A, 11B; 35A, 35B; 50) are formed and arranged relative to each other such that when traction means portions (ZA1, ZA2) of the traction means (Z, Z') are displaced out of the guide channel in the direction of the securing element (2A, 2B) and the traction means (Z, Z') hence abuts against the securing element (2A, 2B), the securing portion (11A, 11B; 35A, 35B; 50) still blocks the traction means (Z, Z') against a displacement transversely to the guide plane (xz-plane) out of the guide channel. - a carrier, - a flexible traction means (Z, Z') for the transmission of an adjusting force for the adjustment of the window pane, and - a deflection piece that is non-rotatably arranged on the carrier and includes a guide channel for the deflection of the traction means (Z, Z') in a guide plane (xz-plane), - the deflection piece is made of a polyaryl ether plastic and - for holding the traction means (Z, Z') in the guide channel at least one securing element (2A, 2B) on the carrier and at least one securing portion (11A, 11B; 35A, 35B; 50) are provided, wherein - the at least one securing element (2A, 2B) extends in a spatial direction (-y) that is substantially perpendicular to the guide plane (xz-plane) and faces the guide channel of the deflection piece, - the at least one securing portion (11A, 11B; 35A, 35B; 50) protrudes from an edge of the guide channel in a spatial direction (-z) that extends substantially parallel to the guide plane (xz-plane), and - the at least one securing element (2A, 2B) and the at least one securing portion (11A, 11B; 35A, 35B; 50) are formed and arranged relative to each other such that when traction means portions (ZA1, ZA2) of the traction means (Z, Z') are displaced out of the guide channel in the direction of the securing element (2A, 2B) and the traction means (Z, Z') hence abuts against the securing element (2A, 2B), the securing portion (11A, 11B; 35A, 35B; 50) still blocks the traction means (Z, Z') against a displacement transversely to the guide plane (xz-plane) out of the guide channel. - the at least one securing element (2A, 2B) extends in a spatial direction (-y) that is substantially perpendicular to the guide plane (xz-plane) and faces the guide channel of the deflection piece, - the at least one securing portion (11A, 11B; 35A, 35B; 50) protrudes from an edge of the guide channel in a spatial direction (-z) that extends substantially parallel to the guide plane (xz-plane), and - the at least one securing element (2A, 2B) and the at least one securing portion (11A, 11B; 35A, 35B; 50) are formed and arranged relative to each other such that when traction means portions (ZA1, ZA2) of the traction means (Z, Z') are displaced out of the guide channel in the direction of the securing element (2A, 2B) and the traction means (Z, Z') hence abuts against the securing element (2A, 2B), the securing portion (11A, 11B; 35A, 35B; 50) still blocks the traction means (Z, Z') against a displacement transversely to the guide plane (xz-plane) out of the guide channel.