How to use the tachymeter of a watch?

The tachymeter is an instrument present on many chronograph watches. If you are a fan of beautiful timepieces, you probably own some. We explain in this article how to use the tachymeter of a watch.

In this article, you shall learn about

  1. What is a tachometer?
  2. How to use the tachymeter of a watch?
  3. The different types of tachometers

What is a Tachometer?

How to use the tachymeter of a watch

A tachymeter is a measuring tool for determining the speed of a moving object or person. Typically, it is the instrument found on car dashboards that indicates the number of km/hour. Many chronographs watch also incorporate a tachymeter.

How to use the tachymeter of a watch?

To use the tachymeter of a watch, it is necessary to activate the chronograph on a first physical mark then stop it. The average speed between the two benchmarks is thus obtained. Classically, it is recommended to select benchmarks separated by a distance of 1km (1000 meters). Otherwise, a little mental calculation is required.

Concretely, imagine that you are in a car or that you are preparing to do a furious sprint. Before using a tachometer, first, locate two elements separated by a distance of 1km. Then activate the push button to start your chronograph when you start from the first mark. Realize the distance of 1km and press the button on your watch again to stop the chronograph when you arrive at the second marker. By looking at the position of the second hand, you will obtain the average speed at which you traveled the distance of 1000 meters between the 2 markers.

If the needle is on 60, you will have done 60 km/hour, if it is on 20, you will have done 180km/hour, if it is on 50 your speed will have been 75km/hour, etc.

A conventional tachometer can only calculate speeds above 60 km/hour. However, it is possible to measure lower speeds by decreasing the unit of measurement.

The different types of tachometers

The tachymeters present in chronograph watches take the form of a graduated scale located around the circumference of the dial. They are usually graduated to measure speed over a distance of 1km, but some models can be marked in miles or for a distance of 100m. There are thus different types:

  • the scale tachometer specified on a basis of 1000 meters,
  • the tachymeter with an unspecified scale , it is therefore assumed that the measurement is made over 1000 meters,
  • the two-scale tachymeter measuring speed over a distance of 1000 meters and 100 meters.

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