Know your watch: Want to know how to use the tachymeter? 

Besides the obvious task of knowing the time of day precisely, sport watches, included Giorgio Piola’s, have a lot more uses. One of them being measuring speed and travel distance. This is particularly useful if you are taking a ride on your car, for example, and this is made through the tachymeter on your watch.

But first, what’s a tachymeter? 

In a watch, a tachymeter is a numerical scale placed in the outer part of the watch face or the bezel. These numbers actually represent speed, and oscillate between 60 and 500. This allows to measure the average speed based on distance traveled. This is possible in conjunction with the chronograph of the watch. It’s much simpler than it sounds, really.

How do tachymeter watches look? 

Tachymeter watches are different than common watches in that they have the tachymetric scale printed or carved on the bezel, but it must have practical use, since many watches just use it with aesthetic purposes. If you want to make sure an analogic watch has this feature you need to check if it has a chronograph too, since the tachymeter uses those same functions to begin and stop the movement of the watch hands.

How do you use the tachymeter? 

We’ve already established that the watch can measure time and speed thanks to the tachymeter’s numerical scale, so we just need a fixed distance through which we’ll make it work. Like the mileage signs from a highway, for instance.

This is a simple mathematical operation in which we will always be able to know any of the three variables of the process (time, speed and distance) by having the other two. While time is a variable that will always be available to you, the other two are dependent on the scenario. That means that if you want to know the traveling speed of an object, you first need to know the distance traveled and the time, and to measure the traveling distance of an object, you first need to know the traveling speed and the time. Pretty simple, right?

Theres a condition when using tachymeter watches, though, and that’s the fact that the measuring time should always be bigger than 7,2 seconds, since that’s the minimum time the tachymeter scale establishes before showing the first number.

Measuring speed

The best way to do this is from a moving vehicle, like a car or a motorcycle, by using the mileage markers from the highway because between each of them there’s a mile or kilometer, and since this scale is neutral, it can adapt to both:

• Set the watch to chronograph with the watch hand in the starting position.

• Start it when you pass the first mileage marker.

• Stop it when you pass the next mileage marker, that is, just finishing the first kilometer or mile.

• Watch the scale and the number where the hand stopped. That’s the average mph/kmph speed at which you traveled.

Measuring the traveling distance is even simpler, though it uses the same process. You know the average traveling speed, and let’s say that it’s a constant speed of 120 mph. You must stop the chronograph when it’s exactly 120 on the tachymeter. Every one of these cycles represents a mile traveled. Pretty easy, huh?