How to Use a Tachymeter, Telemeter, and Pulsations Scale

Possibly the watch world’s most common scale, the tachymeter is proudly featured on golden age chronographs designed and manufactured for motorsport such as Omega’s Speedmaster, Heuer’s Carrera, and Rolex’s Daytona. The key word here is speed. The tachymeter calculates speed or, more generally, units per hour.

Example: Speed of a car, say an F1 car, on a 1 mile track.

• Start the chronograph when the car passes the starting line on a new lap.
• Stop the chronograph when the car passes that same starting line the next time around.
•  The chronograph seconds hand now points to the average speed of the car over the 1 mile lap; for example, 25.5 seconds on the Rolex ref. 6234 is about 140 miles per hour.

Example: Speed of a plane.

• Sitting in row 22 seat C staring at the interactive map on your seat back, the miles to your destination is counting down in increments of 5 miles.
• Start the chronograph when a new 5 miles starts on the map.
• Stop the chronograph when it ticks up indicating 5 miles have been covered.
• The plane took 32.5 seconds to cover this 5 miles, the tachymeter shows 110 at 32.5 seconds.
• After a simple calculation of 110×5, the speed of the plane was 550 miles per hour over the span of that 5 miles.

In general, use a tachymeter by following this process:

• Start the chronograph at a marker
• Stop the chronograph at a marker
• The tachymeter value at which the second hand points indicates speed per the unit measurement between the markers used.

Often featured alongside a tachymeter or other chronograph scales, the telemeter scale is used to approximate the distance between the watch and something that can be heard or seen. The unit of measurement is often kilometers and indicated right on the telemeter scale, normally right near the start. Finding its way into the watch world as a necessity calculating fire range on the battlefields of WWI and WWII, the telemeter can be used in civilian life to approximate distance from lightning strikes, fireworks, among other uses.

Example: Fire range of artillery.

• Start the chronograph upon seeing the explosion of your artillery shell down range.
• Stop the chronograph upon hearing the explosion.
• The chronograph hand points to the approximate distance from you to where your shell has impacted. If 51 seconds have passed the telemeter value is 17, the shell impacted approximately 17km down range.

Example: Distance from lightning strike.

• Start the chronograph upon seeing a strike of lightning.
• Stop the chronograph upon hearing thunder.
• If 21 seconds have passed the telemeter value is 7, the lightning strike was approximately 7km from where you are.

In general, use a telemeter by following this process:

• Start the chronograph upon seeing an event.
• Stop the chronograph upon hearing the event.
• The telemeter value at which the second hand points approximates the distance between your position and the event, in the stated units of the telemeter.

Whereas other scales discussed here can be used for a few to many different applications, the pulsations scale is laser focused in its aim. The history of heart rate calculation and, specifically, using watches to do so is rich. Dr. Andrew Hantel, my good friend, recently wrote a complete breakdown doing a much better job than I could ever detailing this history. That being said, let’s stick to the basics and learn how to use a pulsations scale to find a heart rate.

• Find a pulse.
• Start the chronograph.
• Count the number of beats stated right on the scale of the watch (usually 10, 15, or 30).
• Stop the chronograph after the stated number of beats.
• If using a “base 15” pulsations scale, 20 seconds having passed would mean a heart rate is 45 beats per minute.

Just as a chronograph complication all together can add both symmetry and grace if done correctly or clutter if done poorly, the addition of scales to a dial has to be executed carefully. There is an art here to pay close attention to when collecting. Artful watchmakers will implement both text color and texture changes to set apart a tachymeter or telemeter track. Varying texture is an aspect of this equation that may only be apparent when viewing a watch in the metal but, when done right, will leave you staring at the dial for longer than you’re willing to admit.

Beyond considering the aesthetic tail winds of adding additional scales to a chronograph dial is rarity. Due to their narrow use cases, pulsations scales are seen less often than tachymeters. Rarity means value in this world of vintage, especially when couples with demand. That demand is present for doctor’s watches. Back in 2016, Phillips auctioned a Rolex Daytona ref. 6239 nicknamed “The Doctor” fitted with a pulsations dial. The lot hammered for right around 20x market price of an ordinary ref. 6239 Daytona.

In considering your next vintage chronograph purchase, alongside collectability, pay close attention to the original intended use of the watch. Although the pure utility may now be rendered hollow by the computer in your pocket, the design ethos remains. The Speedmaster and Daytona were designed as companions to drivers. That history and intention can still be felt by a wearer today on and off the track. Similarly, an early Breitling Navitimer is a pilot’s watch, no matter if you understand thrust and lift or have to close your eyes on takeoff and landing.