Tudor added world-time functionality to the Black Bay with the manufacture Caliber MT5652. Not only does the GMT version run more accurately than many other chronometer-tested watches, it boasts a 70-hour power reserve and the time displays can be set in several different ways.
Acting globally and traveling around the world are no longer the exclusive privilege of pilots, top executives and other jet-setting professionals. A GMT function, which lets a watch’s wearer read the time in a second time zone, not only fits well in our globalized age, it’s also a good fit for the Tudor Black Bay. In the spirit of Rolex’s founder Hans Wilsdorf, who established Montres Tudor SA in 1946 as a high-quality but less costly alternative to Rolex, the Black Bay GMT, our test watch, preserves an appealing price-performance ratio while simultaneously encasing the brand’s own manufacture caliber. The Black Bay GMT not only has a time-zone function that’s well suited for everyday use, the model also reaffirms Tudor’s corporate strategy of achieving independence and a distinctive identity for the brand. Tudor relied on movements made by other Swiss manufacturers from its founding until 2015, when Calibers MT5612 and MT5621 became the first Tudor movements encased inside the brand’s watches. After chronograph Caliber MT5813, which was created in cooperation with Breitling, Caliber MT5652 followed suit as a second manufacture movement with an additional complication.
The Time Displays Can Function in Different Ways
Proof that this design is not merely a modular addition to an existing caliber is the fact that when the crown is withdrawn to its middle position and turned manually, the hour hand moves in steps, forward or back, to show a different zone’s time while simultaneously carrying the date display along with it. All this occurs without halting the balance, which means that the exact time is always preserved to the second. We’re familiar with similar mechanisms in other modern movements, for instance, from Omega and Breitling.
The time-zone function can be used in several different ways. The basic option is to utilize the second hour hand as a 24-hour display relating to your local time zone. If you want to quickly display a different time zone, simply twist the bidirectional rotatable bezel until the correct hour digit is aligned with the tip of the 24-hour hand. The bezel’s blue-and-red color scheme immediately shows whether it is day or night in the selected second time zone. The rotatable ring’s 48 individual detent positions let you set it for zones that deviate by half an hour from their neighbors, for instance, India, Myanmar and the state of South Australia. The second option is to use the 24-hour hand to select a second time while keeping the bezel in its original position. The disadvantage of this method is that the movement must be halted when manually turning the crown in its third pulled-out position, which means you’ll have to reset the seconds hand to restore to-the-second timekeeping. The hour hand naturally rotates when the crown is turned in the hand-setting position, so this hand, too, must be restored to its correct local time position and, if necessary, the date switching must also be taken into account.
The Black Bay GMT makes it easy to set a new local time when traveling. All you need to do is withdraw the crown to its middle position and turn it. The main hour hand responds by advancing or retreating in hourly increments while the movement continues to run. The 24-hour hand preserves the home time or the time in a designated second time zone. When you return home after your journey, you simply reset the main hour hand forward or back.
The large knurled crown, which has been adapted from its counterparts on the first Tudor divers’ watches that were waterproof to 200 meters, makes operation very convenient. The crown is screwed into a long tube, but it can be withdrawn smoothly, clicked reliably into its individual positions and securely reinserted by overcoming a spring’s slight but noticeable resistance.
Good Legibility Both Day and Night
The stylized rose atop the crown recalls Tudor’s original logo. Since 1969, the brand has used a coat-of-arms shield on its dials. The shield is used on the dial of our test watch, which was also inspired by the divers’ watches that Tudor made in the 1950s.
Striking hour appliqués – eight circles, two rectangles and one triangle – stand out against the dial’s matte black background. Together with the “snowflake” hands, which are filled with luminous material, these appliqués provide strong contrast during the day and bright luminosity at night for optimum legibility around the clock.
Snowflake hands are an unmistakable design feature of Tudor watches, first appearing in 1969. While they can be found on the dial three times, there’s little chance of confusing them. The impressively large, characteristic, snowflake on the hour hand dominates the dial; the second one is constantly in motion on the seconds hand; and the third one moves slowly at the tip of the red 24-hour hand.
The dial’s bezel can be rotated in both directions and boasts a bicolor aluminum inlay in matte navy blue and Bordeaux red. This inlay suits the watch’s styling and is typical of models in the Black Bay line, as is the fine knurling on the bezel’s sides, which transition to the 41-mm stainless-steel case that is pressure resistant to 20 bar. While this watch can descend 200 meters below the water’s surface, it’s still not a full-fledged divers’ watch, although it offers many of the same features, including a one-sided folding clasp with an extension mechanism and a safety catch.
The handsome ensemble of bezel and case is completed by a riveted bracelet which, like many other details on the Black Bay GMT, recalls Tudor’s watches from the 1950s and ’60s. The wristbands of those models were known for the visible rivet heads that connected the various components and for their step-like arrangement. The steel bracelet of the Black Bay GMT tapers from a width of 22 mm at its connection with the case to 18 mm at its clasp.
Today, the bracelet’s massive components are fabricated using modern manufacturing processes. Other straps are available in leather tanned to a shade of brown known as Terra di Siena or in a textile fabric. The textile fabric straps are made in France by a family-owned, 150-year-old company that uses the traditional jacquard weaving technique.
The Movement Runs for a Long Time with Little Deviation
The caseback of the Black Bay GMT is massive and solid. The metal caseback’s sturdiness is praiseworthy, but its opacity lamentably conceals new manufacture Caliber MT5652. This caliber has a skeletonized rotor, but its bridges and plates have been kept simple, thus preserving the stylistic characteristics of Tudor’s previous manufacture movements, which were designed and built to prioritize robustness, durability and reliability. The large balance with variable moment of inertia is held firmly in place under a bridge rather than a cock. This greater stability, along with an antimagnetic silicon hairspring, helps Caliber MT5652 achieve chronometer status. Thanks to its approximately 70-hour power reserve, this watch won’t need winding or resetting on Monday morning after having been left unworn all weekend. By comparison, ETA Caliber 2893, which is frequently used in GMT models, offers only 42 hours of power autonomy. The Black Bay GMT gains less than 1 second per day when fully wound and worn on the wrist, but it deviates from correct timekeeping by 3 or 4 seconds a day after 42 consecutive hours without a fresh transfusion of energy.
The Tudor Black Bay GMT, with the high-quality features of its new manufacture caliber, and also with regard to its other virtues such as legibility, value, user friendliness and wearing comfort, is, therefore, unrivaled in its price class.
Manufacturer: Montres Tudor SA, Rue François-Dussaud 3-7, 1211, Geneva 26, Switzerland
Reference number: 79830RB
Functions: Hours, minutes, central seconds; date display is synchronized with the hour hand, which can be reset in hourly increments to show the time in a new zone; 24-hour hand, 24-hour rotatable bezel
Movement: Manufacture Caliber MT5652, automatic, COSC-certified, 28,800 vph, 28 jewels, silicon hairspring, Incabloc shock absorption, fine adjustment using screws along the rim of the balance, approximately 70-hour power reserve, diameter = 31.8 mm, height = 7.52 mm
Case: Stainless steel, curved sapphire crystal above the dial, solid caseback, water resistant to 200 meters
Strap and clasp: Stainless steel, integrated, one-sided stainless-steel deployant clasp with safety catch and length-adjustment mechanism
Rate results (deviation in seconds per 24 hours, fully wound/after 24 hours):
On the wrist +0.6
Dial up +4.4 / +4.9
Dial down +1.2 / +1.8
Crown up +0.1 / +1.5
Crown down +0.0 / +0.3
Crown left -1.5 / +1.8
Greatest deviation 5.9 / 4.6
Average deviation +0.8 / +2.1
Flat positions 279° / 266°
Hanging positions 253° / 227°
Variations: With leather strap or textile fabric strap ($3,625)
Dimensions: Diameter = 40.96 mm, height = 14.52 mm, weight = 188 grams
This review originally appeared in the August 2019 issue of WatchTime. Original photos are by Olaf Köster.