What is the purpose of a watch bezel?

What is the purpose of a watch bezel?

A bezel is a top ring on a watch that surrounds the crystal. On a watch, some are clasped or screwed on, some are fixed, and some can be turned in any direction. All watches have some sort of bezel, whether it's a thin ring around the crystal or a ceramic piece that contains the scales.

In general, there are many types of bezels, and they are often associated with specific complications. However, they are rarely decorative, and each is designed for a specific purpose. In this detailed guide, you will learn about the different functions of the most common types of watch bezels.

In addition, we will show you how to use them properly and even how to integrate them into your daily life depending on your activities.

Types of telescope scales
There are many different types of bezels and bezel scales depending on the number of different functions of the watch. Some scales are located at the top of the main bezel and can rotate in one or both directions. Diving watches sometimes have a bezel that is internally controlled by an additional crown. This feature prevents accidental shocks, which can lead to miscalculations.

However, some scales are not located on the top of the case, but on the outer edge of the dial. Instead, they open up the main bezel of the watch to allow for a wider range of case materials and a smooth finish. Nonetheless, it still performs the same calculations regardless of where the scale is located.

Single Notched Bezels
Not all bezels have technical features with scales or numerals. Instead, they showcase historically influenced watch designs. These watches usually only have the time or date and have classic metal bezels that are smooth. In some cases, these bezels also have notches, paying homage to the watchmaking of the time. This refers to the time when the fluted part was used as a handle to remove the watch. The size of these bezels can vary from a thin strip of metal around the dial on the case to a thicker piece of metal around the glass. In addition to the plain or fluted ones, some brands utilized this space by adding diamonds to certain models.

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Rolex Datejust with watch certificate, with a ring and a pair of glasses in the background
Tachymeter
One of the most common scales seen on the outer ring or bezel of a dial is the tachymeter or pocket tachometer. What is a tachymeter? It is a scale on a fixed, non-rotating bezel that is used to calculate the hourly units of a chronograph.

When you look at the scale, you'll see that it starts at marker 1000 at about 7 seconds and ends at marker 60 at 12 hours. This means that it can measure time from 7 to 60 seconds.

It is possible to use this type of scale to measure speed or distance, but some measurements may require more math equations than others.

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Omega Speedmaster watch with watch certificate steel front
Pulsemeter
The pulsometer is one of the rarest scales on a watch. It is usually found on watches of medieval design, worn by doctors. This type of addition dates back to the 1920s, when doctors needed to accurately measure their patients' pulses. Like the tachymeter scale, which measures units per hour, the pulse meter measures the heart rate in one minute. The scale was calibrated from 15 to 30 beats around the dial, starting at 200 at about 5 seconds. Doctors would start the stopwatch, count the beats until their watch was calibrated, and then stop the stopwatch. When they stopped, they could read the heart rate per minute by the alignment of the second hand on the pulse scale.

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Tachymeter.
A tachymeter is also similar to a rangefinder and can be confused with the former due to their similar names! This type of scale is less common and is used to measure the distance between visible and audible events. The best way to describe this type of scale is to watch a thunderstorm. For example, when you see lightning, you start the stopwatch and when you hear thunder, you start the stopwatch. The stopwatch then moves to the top of the distance, usually in kilometers.

Decimal/Decimal Bezel
A customized alternative to the tachometer on Speedmasters, the decimal bezel or decimal meter is a relatively rare scale. Not to be confused with the unit of length of the same name, the decimal allows the user to convert time into decimal values. It is easily recognized by its characteristic scale of 100 and is used primarily for scientific and industrial measurements. In combination with a chronograph, time measurements can be easily converted to decimal points or percentages for use in longer calculations. For example, the 6 o'clock position indicates 50, which can be converted to 50% or 0.5 minutes. While some of the more rounded time stamps are easily converted to decimals on a proportional basis, this tool makes the task of more complex time readings relatively simple.

GMT / Greenwich Mean Time
GMT stands for Greenwich Mean Time and is also known as UTC or Universal Time Coordinated.