Why do watch bezels rotate?
Why do watch bezels rotate on some watches yet for others they do not? Explore the unique functions each bezel has on different wristwatches.
The watch bezel is a simple yet revolutionary innovation that transformed the basic wristwatch from just telling time, to making on the spot calculations and measurements.
Found along the outer circumference of the watch, sits the bezel. It is most commonly a metal ring that has a numerical scale flowing around the watch.
The rotating bezel not only offers a way for you to measure a length of time but it does it in a way without compromising the watch’s readability.
Over time, there have been many different bezels created for different purposes. Depending on the watch’s initial design purpose, the bezel could have been made be to measure various different metrics.
Wristwatches once served a very important function of allowing people to tell the time on the go, whatever they were doing. As wristwatches became more popular in society, they began to be used by people in various different professions.
This saw the evolution of wristwatches for many different types of activities, including diving, racing, and flying.
For example, if you are a motorsport enthusiast you would want to be able to measure your speed, but if you were a diver you would want to measure your oxygen.
Non-Rotating and Rotating Bezels feature different applications based on the bezel scales possess.
History of the Rotating Bezel
It is believed that the early designs of the rotating bezel started to make a popular appearance on wristwatches following the invention of the Second-setting watch, made by Philip Van Horn Weems, which uses a rotating disk used to measure GMT waves – assisting in pilots navigation. This feature initially made its debut appearance on the 1927 Longines second setting collection.
Overtime, wristwatches started to focus on providing more value and functionality for people in many different professions. In the 1950’s Blancpain released the first diving watch for amateurs, name the fifty fathom, which was the first to feature a unique unidirectional bezel.
Eventually once their patent ran out, the rotating bezel was taken up by Rolex, featuring on their Zerographe – a very rare Rolex timepiece. Ever since its first use, the rotating bezel has become a staple in any dive watch. It has even earned the ISO 6425, the international mark of quality governing what can be considered a dive watch.
How does a rotating bezel work?
There are three main types of rotating bezel; bidirectional, unidirectional, and ring command. The bidirectional rotating bezels can be turned anticlockwise and clockwise, making it convenient for users to calculate the time elapsed and how much is remaining.
The unidirectional types move in one direction (mostly counterclockwise). This is an important feature because if your bezel gets knocked out of place or is accidentally moved, it will display that more time has elapsed. This is important, especially for anyone who is into scuba diving. The ring command bezel is exclusively found in Rolex watches, and it’s connected to the watch’s internal movement.
This allows for additional setting positions and adjustments without needing crown position, pushers, or additional buttons.
Here are a few of the main ways a bezel has been used:
Aviation bezel: Slide Rule function
The slide rule bezel is one of the often misunderstood and complicated scales found in watches. The bezel rule is two matching logarithmic scales – one on a rotating outer ring and the other remaining stationary on the inner ring.
This type of rotating bezel was a common feature adopted by Breitling when they released Navitimer in the 1950s. The scale was convenient in helping aviation pilots include metric to standard conversions and calculate distance, airspeed, and fuel consumption.
All of this was achieved by rotating the outer ring in relation to the inner ring, which performs quick division and multiplications.
The Seiko Flightmaster SNA411 is a great example of a watch with a rotary slide rule on it. One of the distinct side rule features in this watch is the two small scales on the bezel (bi-directional rotating bezel) making up the slide rule.
Diving Bezel: Count-up function
The count-up bezel scale is common in dive watches, and it’s used to calculate elapsed time. You can differenciate these bezels with the scale of zero to sixty around the bezel – which are the amount of minutes in an hour. It is usually styled with the first fifteen minutes being marked with one-minute increments, sometimes extending to the first twenty minutes.
To understand how to use this dial lets imagine you needed to time your dinner cooking in the oven for 15 minutes (and for some miracle don’t have your phone on you). Well this is a situation where you can then use your watch, by focusing on the minutes hand and the outer bezel.
The first thing you would do is rotate the bezel so that the zero (most commonly appears as a point marker) aligns with the minutes hand of the watch, let’s say it is 17:36. Now you can see the that the 15 marker on the bezel, is at the time 17:51, which is exactly 15 minutes from your current time – when your dinner will be ready.
This type of bezel usually only moves in one direction, anti clockwise, called a undirectional rotating bezel. This feature was created by blancpain, for diving watches to allow divers to monitor their oxygen levels safely as they are ascending and descending in the water. As the bezel can’t be accidently rotated the other way, which could endanger a diver to believe they have more time of oxygen.
Although whilst blancpain held the patent of the unidirectional bezel other brands created their own somewhat effective versions. These can be found in the Omega Ploprof, or the Audemars royal oak.
So, remember when using the count-up bezel, you’ve got to set the zero markers at the minute hand first, and as time elapses, you can read the elapsed time on the bezel.
One of my favourite watches with the count-up bezel would have to be the Aquinus Blue Aquatic ASSASNHBSB003.
Sailor Bezel: Yatch-timer function
If you are a regatta racing enthusiast, you will find the yacht-timer handy.
Along the watch bezel’s outer edge, there is a timer from 10 to 1 that covers 2/3 rd of the bezel. It is, however, important to note that different watch brands create timers in different styles.
When it comes to boat racing, a horn has to be blown to signify the start of a race.The crew’s responsibility is to make sure that they don’t go over the starting line before a second signal to start the race.
In most cases, the timers will take note of the remaining time before starting a race.
A great example of a yacht-timer is the Rolex Yacht -Timer II. One of the features that stands out in this watch is its countdown timer, making it possible for the wearer to calculate the sailing time between buoys.
Medical Bezel: Pulsometer function
The other rare but useful scales included in a watch is the pulsometer. These scales are common in medially-designed watches worn by medical professionals. These watches have been there since the 1920s and healthcare professionals have been using them to measure a patient pulse. The pulsometer scale measures the heart rate within a minute with the scale calibrated from fifteen to thirty pulses around the dial.
When using the watch, a doctor starts the chronograph then counts the beats to what their watches were rated before stopping the chronograph. Once stopped, they can read the heart rate per minute as per the second hand lined in the pulsation scale. An excellent watch that features this scale is the Scrub 30 pulsometer watch.
It’s highly convenient to take a pulse reading with this watch because of its accuracy. For instance, when the second-hand passes the twelve o’clock mark, you are required to count thirty beats then read the corresponding number on the outer ring.
Motorsport bezel: Tachymeter function
Probably the most recognizable watch known for motorsport racing is the Rolex Daytona.
The Tachymeter was used back in the day by racing car drivers to tell them how fast they were going.
These watches usually run down to 60. The outside numbers allow the wearer to gauge their speed and distance traveled.
Now to understand how a tachymeter works imagine you want to time how fast you have driven in one mile To time your speed you would monitor your second’s hand, and once you reach a mile, you look at what number the pointer is aligned with on the bezel, which would tell your speed. For instance, if the driver takes 30 seconds a complete a mile, they will be traveling 120 miles per hour.
Different watches feature unique traits that makes them best suited for use by people in different professions. It is also important to note that different brands have scales which are exclusive to them, making them highly sort after by people of particular professions.
Perhaps my personal favorites are the Breitling Navitime and Luminox 3001 dive watch. With the Breitling Navitime featuring the slide rule bezel style, perfect for pilots. Whilts the Luminox 3001 is the perfect dive watch with a water resistant to 200m, which means that if you’re a beginner diver, the watch will suit you perfectly.
Written by Max Laird
Founder of Wristwatches360 & keen luxury watch enthusiast.