Put simply, the bezel is the top ring that surrounds the watch crystal, which up until the 1950's, remained soley aesthetic. It was around this time that watch manufacturers realised the bezel was the perfect place to add useful features, without complicating the movement or dial of the watch.
Popular Bezel Types
Elapsed Time Bezel:
The elapsed time (or 'divers') bezel allows the user to calculate the (you guessed it) elapsed time. It features a large, easily readable scale from 0 to 60.
This style bezel was designed to help divers track time spent underwater, commonly with denser markings for the first 10-20 minutes to assist with decompression stop timings.
Dive watches often feature uni-directional rotating bezels to ensure any accidental knocks "add" to the elapsed time rather than reduce. It's always better to end a dive a little early than find yourself running low on oxygen.
How to use an elapsed time bezel:
Whether you're timing a dive or timing your steaks on the grill, simply rotate the bezel so the zero matches the current minute hand. The minute hand will then point to the elapsed time on the bezel.
Tachymeter Bezel:
(This one is less complicated than it first seems, so please stick with it)
A tachymeter is the most common scale and is used to convert speed into distance, and vice-versa. This function is primarily used with watches that have a center seconds chronograph with stopwatch capabilities, and usually appears on a fixed, non-rotating watch bezel (or on the outer rim of the dial).
How to use a tachymeter:
The numbers on the tachymeter represent 3600/elapsed time (seconds)
(3600 = number of seconds per hour)
Let's say you wanted measure the speed of a racing car over a 1 mile stretch.
Ensure the center seconds starts at 0 as the car starts it's journey and stop the chronograph once the car has passed the mile marker.
If, for example, the car takes 21 seconds to cover this distance, the tachymeter will read ~170, indicating a speed of 170mph.
This simple yet ingenious design can prove useful measuring the average amount of time it takes to do anything over the period of an hour.
GMT Bezel:
A GMT watch allows the wearer to keep the time in two or three different time zones – very useful for frequent travelers, pilots or even those who do business in other time zones.
All watches with GMT functionality have either a large rotatable bezel, featuring a 24 hour engraving, or an additional hand that completes one full rotation every 24 hours, or both.
How to use an GMT bezel:
To utilise the bezel, simply move the scale forward or backwards in line with the time difference of your desired country, and you’ll be able to read the time there with ease. Similarly, for watches with an independent GMT hand, you can set this to the second timezone.
If your watch has both a GMT bezel and an independent GMT hand, you can utilise both functions to set 3 time zones.
In all cases, the minutes hand is read as normal.
Slide Rule Bezel:
The slide rule is one of the most complicated scales found on a watch. First appearing on watches in 1952, the slide rule helps pilots with various flight calculations including fuel consumption, air speed and distance travelled, but can be used for multiplication/division or for imperial to metric conversions.
Although pilots are still taught to use the slide rule, for most, the function has been replaced by the much more user-friendly calculator.
If you really want to, you too can learn how to use the slide rule, but, it'll require a bit more than a short paragraph so we're not going to cover that today!
Purely Aesthetic Bezel:
At the end of the day, selecting a watch is, and always will be, a very personal choice and an additional function on the bezel can be anything but subtle.
In many cases a purely aesthetic bezel may be just what to need to complete a stunning timepiece (particularly if you’re not going to be converting distance to speed or need to know the time halfway across the world on a regular basis).
