Dr. Ito's thorough analysis of mechanical watches!! Vol.34 ~ About the "bezel" of wristwatches Vol.2

Good evening everyone!

This column talks about mechanical watches from an engineer's point of view. This is the 34th installment.

"About the bezel Part 2"

I will talk about this topic.

Last time, we introduced the role of the bezel and some of the designs that are commonly seen in dress watches, but this time we would like to introduce bezel designs that are often used in sports models.

First, as a review of what we learned last time, let's explain the function of the bezel.

What is a bezel?

"Bezel" refers to the ring-shaped part around the crystal (glass) of a watch.

Originally meaning "frame" or "border," it refers to the outer frame of the LCD display of a computer or smartphone, but in the case of a watch, it refers to the outer edge of the dial, which corresponds to the face of the watch, or on the surface, the part that surrounds the outside of the crystal.

Its original role was to secure the crystal in place, but as watches have become more multifunctional and designs have evolved, the role of the bezel has changed over the years, and a variety of bezels have appeared, including those with scales that provide measurement functions and those adorned with precious stones such as diamonds.

Now let's take a look at what types of bezels are available for sports models.

Bezel design for sports models

1. Tachymeter bezel

A function that measures average speed per hour, which is displayed on the bezel of the chronograph model. By reading the numbers on the tachymeter, you can determine the speed per hour without doing any calculations. In the case of Rolex, it is written "UNITS PER HOUR", while other watches are written "TACHYMETRE" with the numbers written underneath.

Many chronographs are equipped with a tachymeter bezel and a chronograph hand, and when you press the stop button after traveling 1 km, the value indicated by the chronograph hand is the "distance traveled per hour," or average speed.

There are Rolex Daytona bezels with numbers such as "200 Taki", "300 Taki", and "400 Taki", and it is said that the numbers increased as the average speed of racing cars increased. Nowadays, rare bezels from the transitional period are traded at very high prices.

2. Bidirectional rotating bezel

A bezel that can be moved in both directions, and by aligning the hour and minute hands with the scale, you can read the elapsed time. This is useful for simple time measurement.

It's surprisingly useful in everyday life, too, for example, rotating the bezel during a break at work so you don't forget what time it was to go on a break.

Representative models include Rolex's Turn-O-Graph and Yacht-Master (early models had anti-reverse bezels).

3. Unidirectional rotating bezel

A unidirectional rotating bezel allows you to read the elapsed time by aligning the hour and minute hands with the scale engraved on the bezel of a diver's watch.

The numbers on the bezel are in 1-minute increments from 0 to 15 minutes, and in 5-minute increments above that. The unidirectional rotating bezel only moves in one direction (usually counterclockwise) to prevent the bezel from rotating accidentally while diving.

The reason why the watch only rotates in a certain direction is for safety reasons . If you rotate it forward, it will only shorten the expected dive time, but if you rotate it backwards, you may mistakenly think that you have not progressed as far as you expected, and you may end up diving for a long time. To prevent such malfunctions, it is now standard for diver's watches to have a reverse rotation prevention device.

Representative models include the Rolex Submariner, the Omega Seamaster, and the Blancpain Fifty Fathoms.

4. GMT bezel

A bidirectional rotating bezel with a 24-hour notation that, in combination with the 24-hour hand, allows the time in a second time zone to be read.

By the way, in the case of the GMT Master II, by using a bidirectional rotating bezel in combination with an hour hand, it is possible to read the time in a third time zone. To make it easier to distinguish between AM and PM, the top and bottom of the bezel are often different colors.

Representative models include the Rolex GMT-Master II and the Breitling Chronoliner.

GMT watches often have a GMT hand that can display a second time zone, and a GMT bezel that can display a third time zone.

However, there are also models, such as the Rolex Explorer II, that have a fixed bezel and use a GMT hand to display a second time zone.

summary

This time, we have introduced some of the designs that are often seen on sports models out of the many bezels available. There are many other bezels out there, so if you are interested, why not pay attention to the bezel when looking for a watch?

We hope that this article has been useful to you and has piqued your interest in luxury watches! If you have any questions, please feel free to contact us directly and we will answer them thoroughly. We look forward to your visit and inquiries.

Look forward to the next one! See you next time!