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What is that actually?

On many wristwatches, a scale of around 500 to 60 can be found on the slanted edge of the dial or directly on the edge of the case. This is the so-called tachymeter scale - it not only serves as an attractive decoration on men's watches, but also has a practical function. We explain exactly what the tachymeter is all about in today's blog post.

What is a tachymeter anyway?

A look at the history of the tachymeter quickly reveals that measuring speeds has a long tradition. The origin of the word lies in ancient Greek, where the term "tachymeter" is made up of the Greek words "ταχύς tachýs" for fast and "μέτρον métron" for measure or scale.

The tachymeter is usually located directly on the bezel or the outer dial of a wristwatch. The tachymeter scale and its speed information are therefore easy to see and cannot be overlooked. An additional stop function is required for measuring speed. Although you could wait until the second hand has made a full rotation when measuring speed, this is much more convenient with the stop function. This is precisely why the tachymeter scale can be found on almost all chronographs.

How does a tachymeter work?

Now we come to another important question: How exactly does this tachymeter work? The tachymeter scale represents the reciprocal of the hour that has passed since the start of the time measurement. Normally, the counting begins at exactly 12 o'clock. However, there are also some wristwatches where the tachymeter scale begins at 6 o'clock.

An example to illustrate:

After 15 seconds, 1/240th of an hour has passed, because an hour has a total of 3600 seconds. For this reason, the value at 15 seconds is 240. After 30 seconds, 1/120th of an hour has passed, so the value on the scale is 120.

How can speed be calculated using a tachymeter?

To measure speeds, you need to know the respective distance length. This process is easiest with a distance length of 1 km, because in this case no further conversion is necessary. However, if the distance length is different, the value read on the tachymeter scale still needs to be converted. For the sake of simplicity, we will use the distance length of 1 km mentioned above in our following example:

Let's imagine that we have covered a distance of 1 km in 40 seconds. In this case, our tachymeter would show a value of 90:

90 x 1 hour x 1 km = 90 km/h

This calculation method is not only used to measure car speeds, but also ships. It can also be used to determine the speed of a filling process.

Of course, the tachymeter is not only designed for measuring high speeds, but can also be used for running or hiking routes. All that is required is to adjust the reference value of the measurement.

Example : Let's imagine that we run a distance of 200 m in 50 seconds. In this case, the tachymeter scale would show the value 72:

72 x 1 hour x 0.2 km = 14.4 km/h

Once you know the length of the route, you can easily calculate speeds.

FAQ

In the last part of our blog post, we would like to address the most frequently asked questions about wristwatches with tachymeters. These include the following:

Are there alternatives to the tachymeter?

Nowadays, tachymeters are used less and less. Understandably, because in the modern digital age of smartphones, navigation devices, etc., there are now much simpler options. Nevertheless, the tachymeter in watches is still a nice gadget and the tachymeter scale is an attractive decoration.

Who can particularly make use of a tachymeter?

Watches with this practical function look particularly good on the wrists of runners and sports pilots. Furthermore, speed measurement using a tachymeter is also useful on the water, for example for captains. The same applies to measuring the speed of flow. People who often have to deal with water in their job can certainly benefit from such a chronograph.

Which brands like to use watches with tachymeters?

Special tachymeters can be found on Alpina watches, for example. But Breitling also still likes to produce watches with elegant tachymeter scales. Of course, this also applies to a number of other brand manufacturers.

Why do most tachymeter scales only go up to a maximum of 500?

Most scales on standard wristwatches often only go up to a maximum of 500 units per hour. In most cases, the value is only up to 400. The answer to why is actually quite simple: if the tachymeter scale went beyond this value, the measurement would be far too inaccurate. After all, even small deviations of just a tenth of a second in the range above 500 result in enormous deviations in the units. Accordingly, depending on the watch, the scale only goes up to a maximum of 500.

Can I also measure my pulse with a tachymeter?

When the doctor measures your pulse, the counting begins either when the second hand is at 12 o'clock or 6 o'clock. This means that the pulse can also be easily read on the tachymeter scale.