First released to the public in 1954, the Rolex GMT-Master has undergone countless changes and updates throughout the years as Rolex continuously works to refine and improve its design. The most notable feature of the original GMT-Master was its bright red and blue rotating bezel with 24-hour markings. Although the GMT-Master’s bezel has been manufactured in a number of different colors and materials throughout the years, it has always been the defining characteristic of Rolex’s multi-time zone pilot’s watch.
The very first bezel fitted to the original reference 6542 GMT-Master had an insert made from Bakelite, which had glowing radium numerals set into its plastic-like material. The Bakelite insert was fitted inside a metal bezel ring, which was then held onto the watch with a set of specialized washers that fit under the bezel. Since the bezel was friction-fitted onto the watch, it smoothly rotated bi-directionally, and did not ratchet or click like contemporary GMT-Master references.
This Ref. 6542 Rolex GMT-Master’s bezel was made from Bakelite
After just two years of working with Bakelite, the GMT-Master’s bezel insert was replaced by one made from aluminum, due to issues surrounding long-term durability. The aluminum inserts retained their signature red and blue coloration; however they no longer were set with radium numerals, and consequently did not glow at all. Rolex continued to manufacture the GMT’s bezel insert from aluminum for roughly half a century thereafter; however several additional colors made appearances on later references, starting with the all-black insert that first made an appearance during the early 1970s.
While the GMT-Master’s bezel insert was manufactured from aluminum for roughly fifty years, a new mechanism for the function of the bezel was implemented in 1983 with the introduction of the first GMT-Master II, the reference 16760. Although structurally very similar to the friction-fitted bezel of the previous GMT-Master watches, the new design employed the use of a small flexible spring that allowed the bezel to click into place for greater precision when setting it to reference a secondary time zone.
In 2007, the bezel on the GMT was completely redesigned with the release of the reference 116710. Instead of being made from aluminum, which was prone to scratching and fading, the bezel insert on the new generation of GMT-Master watches was made from Cerachrom, Rolex’s proprietary ceramic material that is highly scratch resistant and will not fade after prolonged use and sunlight exposure.
The new GMT-Master’s bezel is made from Cerachrom
In addition to the ceramic insert, the entire structure of the bezel has been redesigned to improve its overall functionality and remedy some of the shortcomings of its predecessors. Instead of relying on specialized washers and small flexible springs, the redesigned bezel mounts on a set of four bearings for a smoother feel and greater stability. Additionally, while previous ratcheting GMT bezels followed a 120-click design, the ceramic bezel on the new GMT-Master II clicks 24 times per rotation to better correspond with the bezel’s intended function as a secondary time zone display.
A rotating 24-hour bezel has been the defining characteristic of the Rolex GMT-Master line since its initial introduction back in 1954. While it started its life as a simple, rotating fixture around the face of the watch, the GMT’s bezel has undergone a number of updates and changes over the years, and has evolved into a highly specialized component that has been uniquely engineered to aid with the watch’s multi-time zone capabilities. The variety of different colors and materials that exist for GMT-Master bezels creates a wonderful diversity among the various GMT-Master watches, and adds to the overall excitement and pursuit for collectors.