Why We Love the Rolex GMT-Master 1675 Pepsi 'Mk1' Tropical 40mm from 1966

1966 was the year the GMT-Master changed its face, when Rolex retired the glossy gilt dial and introduced the matte black that would define the reference for the next fourteen years. This watch carries the very first execution of that new look, the Mk1 'Long E' dial, and six decades of sunlight have turned its matte black surface an even dark chocolate. A first-year matte dial that has gone tropical, sitting under a faded Pepsi bezel, is the kind of combination that makes vintage Rolex so absorbing.

A Watch Built for the Jet Age

The GMT-Master exists because commercial aviation suddenly made the world smaller. In the mid 1950s, Pan American World Airways approached Rolex for a watch that could display two time zones at once, so that its flight crews could keep track of home time and local time as they crossed the Atlantic. Rolex answered with the reference 6542, which added a 24-hour hand and a rotating two-tone bezel to the Oyster case. It worked, but its Bakelite bezel was fragile and its crown sat unprotected.

The Reference 1675 Arrives

In 1959 Rolex replaced the 6542 with the reference 1675, and got it so right that the 1675 remained the only GMT-Master in production from 1959 until 1980. The new reference brought crown guards, a more robust anodised aluminium bezel insert, and a case that settled into the 40mm dimensions still associated with the model today. Across its twenty-one year run the 1675 evolved constantly in small ways, which is why individual examples, like this 1966 watch, can be pinned to their exact moment in the timeline.

The Pepsi Bezel

The blue and red bezel was never a styling exercise. The red half marks the daytime hours from six in the morning to six in the evening, the blue half marks the night, so a pilot reading the 24-hour hand could tell at a glance whether it was day or night back home. The nickname came later, the logic was there from the start. On this watch the insert has softened with age, and its interplay with the chocolate dial gives the piece its warmth.

1966 and the Mk1 'Long E' Dial

Within the long run of the 1675, 1966 is a true turning point. It is the year Rolex moved from glossy gilt dials to matte dials with printed white text, a change that shifted the whole character of the watch from dressy and reflective to tool-like and legible. The first mainstream execution of the new matte dial is known as the Mk1, produced from around 1966 to 1972 and identified by the detail that gives it its name: the middle bar of the E in ROLEX is noticeably longer than on later dials. The Mk1 also carries a coronet with fine, elongated points, another signature of the early matte era.

A 1966 example with a Mk1 dial is therefore a first-year watch in the truest sense, made in the season the design changed. Details like the Long E were never meant to be noticed. They are artefacts of an era when Rolex dials were made by specialist suppliers, which is exactly why they matter now.

The Tropical Dial

Tropical is the word the vintage watch world uses for black dials that have aged to brown, a slow chemical change in the dial lacquer driven by years of ultraviolet light. No two tropical dials age the same way, and many turn patchy or uneven. The desirable outcome, and the one this watch displays, is a uniform shift across the whole dial surface, here to a rich dark chocolate that pairs naturally with the warm cream of the aged tritium plots.

What makes a tropical Mk1 special is that the ageing has happened to the matte finish rather than the gilt gloss of earlier watches, giving the brown a soft, almost velvety quality. It is a face the watch has earned over sixty years, and it cannot be replicated, restored or rushed.

The Calibre 1575 Inside

Beneath the dial sits the calibre 1575, the automatic GMT movement Rolex introduced to the 1675 around 1965, running at 19,800 beats per hour and chronometer certified. It is a movement with a reputation for going about its work for decades, and this example, recently serviced and running within COSC tolerance, is doing exactly that.

Final Thoughts

The GMT-Master 1675 was born from a practical request by an airline and stayed in production for over two decades because the answer Rolex gave was essentially complete from the start. This 1966 watch captures the reference at its pivot point, wearing the first of the matte dials, and time has since added something Rolex never could: a dark chocolate tropical dial that belongs to this watch alone. That mix of aviation history, first-year detail and one-of-one ageing is why we love it.

• Case in excellent vintage condition.
• Extremely sharp lugs with hand brushing visible.
• No pitting or corrosion at all.
• Both serial & Model Numbers remain intact and legible.
• Bracelet in good vintage condition, some stretch as to be expected with age.
• Watch easily passed a 5BAR pressure test
• Watch has been serviced within the last 12 months & is running within COSC tolerance.

• Dial & hands excellent condition 
• Dial has developed dark chocolate tropical patina