The editors of Chronos Japan raved about the Tudor Black Bay 58 GMT, which was released in 2024. To be honest, a major reason I planned this feature was to cover this model. With its high magnetic resistance, independent time zone adjustment function, and instantaneous date advance, this watch is currently the most powerful GMT watch available.
A new model for 2024. It features an instantaneous date display, a separate time zone adjustment function, and even meets Master Chronometer standards. By using the compact Cal. 5400 series as a base, the thickness of the watch itself has been kept down to 12.8mm. Automatic winding (Cal. MT5450-U). 28,800 vibrations/hour. Power reserve of approximately 65 hours. Stainless steel case (diameter 39mm, thickness 12.8mm). 200m water resistance.
Photographs by Eiichi Okuyama
Masamasa Hirota (this magazine), Yukiya Suzuki (this magazine): Interview and text
Text by Masayuki Hirota (Chronos-Japan)
Text & Edited by Yukiya Suzuki (Chronos-Japan)
Edited by Yuto Hosoda (Chronos-Japan)
[Article published in the July 2025 issue of Kronos Japan]
Tudor's ultimate GMT watch
Tudor's "Black Bay 58 GMT" is an extremely groundbreaking GMT watch in two respects. First, it meets the Master Chronometer standard, which requires high magnetic resistance of 15,000 gauss. Second, it combines independent time zone adjustment with instantaneous date switching. While there are models that have one or the other, this is the only one that combines high magnetic resistance with ease of use. The Black Bay 58 GMT is a truly unique GMT watch.
Below, I would like to offer my opinion, including some speculation. Tudor explains that the real challenge came when this movement needed to obtain METAS Master Chronometer certification. "To bring the movement to the stringent standards of Master Chronometer certification, it was necessary to redesign the 5400 series movement, especially this caliber, to even stricter standards." The specifics of how it was redesigned are unknown, but it can be speculated that ceramic was used for the balance staff.
The GMT mechanism is also excellent. The Caliber MT5450-U, which it uses, has a function that allows you to advance or rewind the hour hand in one-hour increments by pulling out the crown and turning it. The date also changes in conjunction with this movement. This mechanism, developed by Rolex, has now been adopted by many GMT watches. In addition, the Black Bay 58 GMT is new in that the date changes instantaneously. However, the date does not change instantly by advancing the hour hand alone; it only changes instantly when the hands are rotated normally. The reason for not including a quick-change function for the date only is to avoid setting a prohibited time period for manipulating the date. "Because not all users will follow the instructions for use," (Tudor).
The Cal.MT5400 series, unveiled in 2018, is a next-generation movement with a diameter of 26mm yet boasting a power reserve of approximately 70 hours, a sufficiently practical length. This is the reason Tudor has been able to release smaller models. This particular watch adds a GMT mechanism to this movement. As the photos show, the GMT mechanism is quite large, but according to Tudor, it is different from existing ones. The finish is understated, as befits a practical timepiece.
To advance or reverse the date in conjunction with the independent time zone correction function, one simply needs to slow down a barrel wheel that rotates once every 12 hours, attach a protrusion to a gear that rotates once every 24 hours, and use it to hook and rotate the date display. The design is not particularly difficult. On the other hand, instantaneous date change uses the rotation of the barrel wheel to charge a spring, and the force of its release instantly moves the date display. The date display of the independent time zone correction function, which advances or reverses the date in a short time, and the instantaneous date change, which switches over time, are different designs, and it is quite difficult to make them work together. However, Tudor has achieved this with the MT5652 in the "Black Bay GMT" and the MT5450-U in the Black Bay 58 GMT. According to Tudor, approximately 20 hours of power reserve is required for the instantaneous date change mechanism to function properly.
However, Tudor did not simply transfer the GMT mechanism from the 5652.
"Adapting the same system and structure to this smaller movement required a lot of ingenuity. There were difficulties in the process of adapting this module to the small movement, but ultimately it became clear that a scaled-down version of the original system was the optimal solution." This is purely speculation, but it is likely a GMT mechanism that draws power from a barrel pinion, similar to Rolex's 3200 series.
The Black Bay 58 GMT has finally been released. Its retro look will surely appeal to watch enthusiasts. However, the people who really need this watch are business professionals who travel the world. This GMT watch, with its user-friendly features and high magnetic resistance, is truly a practical timepiece in every sense of the word.
