Abstract: Embodiments of the present invention provide systems and methods for installing seats in a passenger vehicle using seat tracks and seat fittings. The seat track fittings may include a sleeve (22) with a cylindrical threaded opening (24), a double effect post (26) with an external lower thread (28) and an internal threaded portion (36). The external lower thread is configured to cooperate with the cylindrical threaded opening of the sleeve. The seat track fitting also has a track stud (38) with a lower flange (46) that is configured to cooperate with a seat track (10) and an upper external thread (42) configured to cooperate with the internal threaded portion of the double effect post. The double effect post external lower thread and the track stud external thread have inverse hands, such that rotation of the double effect post tightens the post and the track stud simultaneously.