How to Use a Tachymeter Watch Bezel

A Tachymeter scale is a scale sometimes inscribed around the rim of an analog chronograph watch. It can be used to compute a speed based on travel time or measure distance based on speed.

The function performed by a Tachymeter is independent of the unit of distance (e.g. statute miles, nautical miles, kilometres, metres etc.) as long as the same unit of length is used for all calculations. It can also be used to measure an industrial production process in units per hour. A tachymeter is simply a means of converting elapsed time in seconds per unit, to units per hour.

A tachymeter-equipped watch can be used to measure distance by timing the travel over the distance while the speed is held constant. When the second hand reaches the point on the scale where the speed indicated equals the speed of the vehicle, one unit of distance (miles if speed is miles per hour, kilometres if kilometres per hour, etc.) has been covered. For example, if you travel at a constant 80 mph (or at 80 km/h), then the distance traveled while the second hand sweeps to "80" (45 seconds) will be exactly 1 mile (or 1 kilometer at 80 km/h).

[Lilbizkit]

I used my tachymeter to calculate that the narrator was talking at a rate of 137 words per second.

[jars]

Just what I thought. It makes a watch looks cool.

[timsummers]

A tachymeter is something that 99.99% of the people who have it on their watch never needed or knew how to use it. After watching this video, 99.99% of said people will continue to never use or need it, let alone understand what the fuck a tachymeter is good for.

[adammchugh]

As someone trying to learn more about watch movements for my work, this was tremendously helpful. Thanks!

[pookspookspooks]

this is the HYPEST tachymeter video out there

[mrmoxley]

Thanks. Simple and to the point. I thought there was some complex way of using the bezel.

[MyNiceguy]

Now I finally know wtf that thing on my watch does... thanks, great video

[markdoughty]

Very useful upload; made a seeming enigma (the tachymeter on a chronograph watch), a lot clearer - many thanks.

[xocoyotl]

I want to know how many lines per hour I write. So I'm buying a $25, 000 Rolex Daytona to do the measurement.

[rohanghige]

Pro tip: Watch video in 0.5x speed and you will understand it better.

[treatb]

It actually measures average speed. Which is nice for fuel consumption. Along with timing laps. But if you then know an average speed. You can calculate the distance you will be driving and how much fuel you need. I do that all in my head but a watch is fun.

[notsopassive]

This guy's voice is hilarious. Sounds like something from South Park.
Every sentence ends with his voice dropping into bass

[zzolioo]

I think i didn't had my coffee yet as I don't have a clue what is that tachymeter doing even after watching this video :))

[dana]

Why I am watching this video.... I don't even have a watch.... 🙄

[billybenson]

Little known fact is it helped getting Apollo 13 back home safely. If one is a pilot or on the ocean and loses navigation abilities, it comes in handy on plotting a course.

[esrynshudder]

why tf is it so dramatic, it's just something on a watch chill

[MariusWM]

Appreciate the short and precise explanation. But Im still wondering if anyone at all uses this on their actual watches?

[fruitlp]

I'm honestly a little bit confused...
Could it be used to calculate distance traveled over a 6 or 9 minute interval, perhaps, given a constant speed?

[nowiemesina]

I have a winner skeleton golden watch and it has tachymeter idk where to press it use the tachymeter pls help me

[ronch]

Well, cars often travel at variable speeds so I honestly wonder what tachometers are good for.