Watch Bezels That Add Functionality

When it comes to functional watch bezels, dive watches are the most common. The majority of bezels are simply decorative finishes of a case that surround the crystal, like crown molding in your home (so to speak). Functional bezels, however, almost act as additional complications to measure dive times, speed, distance, multiple time zones and so on. At Horage, we’ve embraced functional bezels for diving and also developed a first in the industry with the Lensman 2 and an exposure calculator (more on that below). Let’s take a look at some of the most popular functional bezels and see just how important they can be to the overall design.

Diving Bezels

Of course, rotating dive bezels are both the most common and recognized of all functional bezels, popularized by early pioneers like Rolex with the Submariner, Blancpain with the Fifty Fathoms and Omega with the Seamaster. For anyone thinking of Panerai, those traditionally lack a rotating bezel. The function of a rotating dive bezel is to simply measure the length of time underwater by rotating the 12 o'clock triangular mark to line up with the minute hand. Some have a detailed 15-minute scale, while others have simple 60-minute scales and so on. There are even reverse scales like on the Eska Amphibian 600 from the 1960s.

Some bezels are internal or under the crystal, rotated by a second crown. This is seen on super compressor divers (where the caseback is influenced by water pressure to form a tighter seal) and copies of the style. Most dive bezels are unidirectional (rotating one way only) to prevent accidental changes underwater. Bidirectional bezels allow for easy timing of other events when security of the initial rotation isn’t paramount.

The Horage Supersede GMT and Supersede Date aren’t dive watches per se, but all-around, all-terrain timepieces that also sport a rotating diver’s bezel and 200-meter water resistance rating. The rotating bezel transforms this integrated sports watch into a bona fide diving tool, above and beyond the integrated complications on the dial. Of course, buyers are never obligated to use a dive bezel underwater and most dedicated dive watches are simply worn for style over actual function. With Supersede, you know that the watch is ready for just about any outdoor occasion, including serious underwater adventures.

GMT (or 24-hour) Bezels

GMT (Greenwich Mean Time) is the standard used globally by almost all nations and time is partitioned into 24 time zones based on the position of the earth and sun. For example, Los Angeles is three hours (or time zones) behind New York. GMT watches really hit the scene when commercial aviation moved to jet propulsion, most notably when Rolex partnered with Pan Am to provide GMT watches to long-range pilots. Unlike a diver’s bezel with a 60-minute scale, GMT bezels have a 24-hour scale. Some have a 12-hour bezel, but that's not considered a true GMT piece. The simplest way to follow a second time zone is to rotate the bezel until the additional hour coordinates with the hour hand. Some watches have a second hour hand (or GMT hand) that can be adjusted independently of the others. This can be used with or without the bezel, but working together with a 24-hour bezel would allow for a third time zone - the regular hands, the GMT hand and the 24-hour bezel coordinated with the hour hand. If the 24-hour bezel is fixed, the independent GMT hand would be a necessity. These bezels are generally referred to as 24-hour bezels, not GMT bezels.

Our Supersede GMT piece (now sold out) again had a diver’s bezel, but also an independent GMT hand and day/night indicator, making it both a diver and true GMT watch. This demonstrates how a functional bezel can really change the dynamic of a watch.

Tachymeter Bezel

Chronograph watches often have a tachymeter on the bezel to measure either speed or distance while in motion. It’s used simultaneously with a central chronograph seconds hand. To measure speed, the chronograph timer is started at an initial marker and stopped at a second point where the distance between the two are known. When that second point is reached, the figure on the scale adjacent to the chronograph seconds hand shows the speed. For example, if it takes 30 seconds to travel a mile, the chronograph seconds hand will be pointing to 120 on the tachymeter scale - hence 120 miles per hour. For general speed calculations, the tachymeter is only good for measurements up to 60 seconds, although some watches have modified scales (scroll or wraparound) to extend this a bit.

To measure distance, the bezel is rotated to align with the seconds hand at the start of measurement. When the seconds hand moves to the point of the scale that is equal to the speed being traveled, it indicates the distance traveled in that time. So, if it takes 45 seconds for the seconds hand to reach 80 while traveling at 80mph, you will have traveled exactly one mile in that time.

Lensman 2 and our Exposure Calculator Bezel

We recently developed an industry first with the photographer’s exposure calculator bezel on the Lensman 2. This allows traditional photographers with manual film cameras to calculate exposure without a separate handheld meter. The bidirectional bezel has both ISO (film speed) and aperture (f-stop) figures from f/1.4 to 22. This works with a fixed inner ring that shows shutter speeds and icons representing lighting conditions (sun, clouds, indoor lightbulb, etc.) You simply align the ISO with the lighting conditions (sun for bright daylight, for example) and you’ll get the optimal shutter speeds and corresponding f-stops. It’s functional, stylish and again an industry first. In addition, the Lensman 2 uses the K2 micro-rotor movement found in the Supersede watches, so there’s an independent GMT hand as well to track an additional time zone. A traveling photographer's dream watch!

This doesn't cover all functional bezels, but does hit on the most popular (and our unique exposure calculator to boot). A telemeter, for example, is sometimes found with a tachymeter and measures distance based on how long it takes sound to travel. A compass bezel allows you to set it at true north (via the sun or established landmark) and use the watch as a field compass. And so on. At Horage, we focus on all aspects of design, including the bezel, to bring you the best engineered in-house Swiss watches at industry leading prices. It's just our mission as a performance watchmaker.

We Want to Hear From You!

Sound off in the comments about additional topics of interest, so we can be sure to cover what you want to read in future articles. And please share this with friends and anyone interested in watchmaking, and let's keep the conversation going. Also, be sure to sign up for our newsletter (here) and keep an eye out for new products as we're always in the process of development. Check out journal entries as well (here) and a detailed section on performance watchmaking at Horage (here).

We'll talk again soon!

Erik Slaven