The Rolex GMT-Master II is one of the most iconic - if not the most iconic - GMT watches in the world. And that’s perhaps not very surprising for a number of reasons.
First off, Rolex is one of the most iconic watch brands in the world. It’s a brand that is known all around the world and praised as one of the most prestigious watch brands in the world.
Secondly, Rolex is actually the company that is responsible for making the first-ever GMT wristwatch. With that said, when a lot of people ask how a GMT bezel work, they often refer to how a Rolex GMT bezel work. But the good news is that essentially all GMT watches are made the same, so regardless of which GMT watch you have, you’ll find this guide helpful.
So how does a Rolex GMT bezel work? That’s what we will look closer at in this article.
Rolex GMT background
Before we dig into the details of how a Rolex GMT bezel works, let’s go through the background and history of the Rolex GMT.
The story of this model goes all the way back to 1954 when Rolex released the first GMT-Master reference 6542. The GMT was released at the request of the iconic airline Pan Am.
Pan Am (Pan American Airlines) contacted Rolex and requested that they made a timepiece for their pilots that was able to keep track of two timezones simultaneously for when the pilots traveled across different continents. Remember, this was a time when airlines started flying across the Atlantic Ocean, to Europe and back, but also to other continents as well. The request was intended to help pilots keep track of their local time but also their home time. - simultaneously.
Rolex’s response to PanAm’s request was the GMT-Master - the first GMT wristwatch ever to be released. The reference was presented with a 38mm case and powered by the base caliber 1030, modified to include a 24 hour hand, which resulted in the caliber 1065.
How a GMT watch works - how does Rolex GMT bezel work
The concept of the GMT is, at least from a functional standpoint, quite simple. A GMT watch is equipped with an additional hour hand, known as the GMT hand, and a bi-directional 24-hour bezel. The 24-hour GMT hand rotates one full rotation every 24 hours.
The home time is indicated by the conventional hour, minute, and seconds hands. The local time is indicated by the 24-hour hand which is read against the graduations on the bezel when in the neutral position.
Not all GMT watches have a rotating bezel, but the Rolex GMT-Master does, which is what we use to set a third time on our watch.
To set the GMT-Master, you first set the regular (home) time. To set the home time, pull out the crown two positions and set the time and date using the GMT hand. The bezel should be in the standard position, meaning the triangle at 12 o’clock. Generally, home time is where you start your journey - your home.
Now, it’s time to set the local time. You set the local time by adjusting the hour hand. To do this, you adjust the jumping hour hand. With Rolex’s newer GMT models, the GMT hand can be adjusted individually without affecting the 24-hour hand or the minute hand (something that was not possible with the early GMT watches). Bear in mind that the date will always correspond to the local time, not the local time.
So how does the GMT bezel work?
As mentioned, when the GMT bezel is in the 12 o’clock position, it will indicate the 24-hour time. But turning the bi-directional bezel of the GMT-Master II will allow you to read the time in an alternative time zone. When you rotate the GMT bezel, the reference time is no longer shown.
Since it is a 24-hour bezel, it has 24 ”clicks” that you will feel when rotating it. Every click is one hour.
To display the alternative time zone, identify the difference in hours between your reference time and time in your desired time zone. For example, if you are in Paris and want to know the time in New York, you may know that New York is 6 hours after Paris. To identify the time in New York, you turn the bezel clockwise 6 hours (6 positions). If you, on the other hand, are in New York and want to know the time in Paris, you turn the bezel clockwise 6 hours (6 positions). The key to using the Rolex GMT bezel is therefore to know how many hours difference there is between your reference time and the location that you want to know the time in.
Simply summarized, you turn the bezel to the left for second time zones that are ahead of your local time and you turn the bezel to the right for time zones that are behind your local time.
The minutes will always be indicated on the dial with the center minute hand as the minutes are always the same, regardless of the time zone.
Remember that the Rolex GMT hand is a 24-hour hand, meaning it will only go around the dial once per day. The purpose of this is to allow the wearer to read AM and PM time, and thus know whether it is night or day in the timezone. This is where a bi-colored bezel comes in handy, which can be found on most Rolex GMT-Master watches. The darker tone on the bezel shows night, and the higher color indicates the daytime hours.
How to use Rolex GMT bezel - summarized
1. Set the watch to your home time using the large 24-hour hand.
2. Set the local time (the second time zone, your current destination) to the time zone which you are in by pulling out the crown to the first notch and setting the standard hour hand to display the date and the time correctly.
3. To see the time in an alternative time zone, figure out how many hours ahead a third time zone is that you want to find out the time in.
4. Rotate the bezel either clockwise our counterclockwise to compensate for the difference in hours. One click on the bezel represents one hour. If a location is behind, you rotate the bezel clockwise, and if the time in the location is ahead, you rotate it counterclockwise.