Cal. 5402 is a compact automatic movement from Tudor.
Introduced in 2018 in the reduced-size Black Bay Fifty-Eight, Cal. MT5402 shares most of its specifications but few of its components with the larger MT5600 family, and specifically Cal. MT5602. Due to this similarity of construction and naming, these movements are often confused for one another, though Cal. 5402 is much smaller, at 26.00 mm diameter by 4.99 mm thick. This makes it as narrow as the dominant 2892 and 2824 family movements from ETA, though somewhat thicker and better in terms of specifications.
Cal. MT5402 is a COSC-certified chronometer and features high-end features like a variable inertia balance wheel with a free-sprung silicon hairspring. It is non-magnetic and boasts a 70 hour power reserve, all features shared with the newest movements from Rolex and Tudor. The balance is mounted on a full bridge for stability. The bi-directional central winding rotor is supported by seven ball bearings and mounted with a central screw.
The Norqain Cal. NN20/1 is based on Tudor’s MT5402 and is produced by Kenissi. It lacks the silicon balance spring and has different finishing.
Chanel’s Cal. 12.1 is a version of Cal. MT5402 with a date complication, two extra jewels, and special finishing.
Comparing Tudor Cal. MT54 and MT56
Tudor launched an in-house movement family in 2015, the MT56 family. These share modern construction details and components with contemporary Rolex movements and have proved very popular. The company created a joint venture manufacture called Kenissi in 2018, and now supplies movements to Tudor, Breitling, Chanel, and Norqain. Also in 2018, Tudor launched a smaller movement, Cal. MT5402, for the compact 39 mm Black Bay line. This movement is a different design and is unrelated to the earlier family, though it shares many architectural similarities. Due to these similarities, these movements are often confused.
A comparison of the 26.0 mm MT5402 and 31.8 mm MT5612, to scale. Note the many visible differences in design and construction, as well as the dramatic size difference.