Tachymeter watches: All about them

Tachymeter | WatchTime - USA's No.1 Watch Magazine

A tachymeter is a type of watch complication that measures the speed of the watch’s wearer over a set period of time. Tachymeters are commonly found on chronographs, which are specialised watches with multiple stopwatch functions in addition to the traditional watch display.

A tachymeter is typically found on the bezel of a chronograph. The bezel is a component that surrounds the face of your watch. Bezels are used to make various measurements, and different watches frequently have different features on their bezels.

Many watch bezels are designed to rotate in order to perform precise measurements and adjustments. Many aviation watches, for example, include a dual-time display complication that can be adjusted by rotating the watch’s bezel. Tachymeters, on the other hand, are found on watches with fixed, non-rotating bezels.

Tachymeters can be used to calculate the average speed of a watch’s wearer over a given time period. Most tachymeters can take measurements from seven to sixty seconds.

Chronograph watches have a measuring hand that can be started and stopped to take precise measurements. You will align this hand with a specific point on your tachymeter scale to use the tachymeter complication on your chronograph. You can then use a simple formula to perform some quick calculations to determine your speed over a specific time period.

Tacymeters Are Used In What Kinds Of Watches?

The racing watch is the most common type of watch with a tachymeter. The racing watch is a perfect timepiece for more than just car enthusiasts, thanks to its sleek design and place in the rich history of competitive driving. A racing watch’s chronometer and tachymeter can be used by anyone to track speeds and times, and these watches are distinctively stylish.

A few key features distinguish racing watches. A high-contrast dial is a trademark of racing watch design, and it is a must-have feature for high-speed drivers. Standard watch faces can be difficult to read when moving at high speeds, but racing watches are designed with competitive drivers in mind, providing them with a highly readable display.

The racing watch design also includes a stopwatch function that can be used in conjunction with multiple chronometers to measure times and distances. A racing watch, in addition to chronometers, has a tachymeter on the bezel. When combined with a stopwatch, the tachymeter can be useful on the racetrack in a variety of situations, allowing for the tracking of speeds at specific points along a driver’s route.

A pulsometer is a less common complication found on some racing watches. This complication is intended to measure a driver’s pulse. However, the pulsometer is not as well-known in racing watch design as the tachymeter or chronometer.

Tachymeter Watch Reading And Application

A tachymeter is a device that is attached to the bezel of a watch and can measure speed based on time travelled over a fixed distance. It is possible to convert elapsed time in seconds per unit to speed in units per hour using this. The tachymeter scales and measures times ranging from about 7 seconds to 60 seconds.

Tachymeters of various types

Since the late nineteenth century, three major tachymeter configurations have evolved. Let’s take a look at them and learn how to use various types of tachymeter scales:

On a fixed bezel, circumferential

The majority of tachymeter scales on a racing chronograph are circumferential around the bezel or dial. This can be on a fixed outer bezel (for example, the Rolex Cosmograph Daytona) or a fixed inner bezel (for example, the Heuer Carrera ref. 1158). When the tachymeter markings are on the outer circumference of the dial (as on the Heuer Camaro Ref. 7220T), the scale operates similarly to a bezel-mounted tachymeter.

Snail tachymeters

On vintage chronographs, a spiralling tachymeter scale is sometimes etched or printed on the centre of the dial – often to complement a circumferential telemeter scale. This configuration is also known as a nailed tachymeter,’ a spiralling tachymeter,’ or a ‘circling scale.’ It functions similarly to a fixed tachymeter scale, but it has a wider range of speeds because it can be used for multiple rotations of the second hand (typically three).

The spiral tachymètre scale is described in the book Universal Genève: 100 ans de tradition horlogère by Bonifacio and Rivolta as follows:

‘To accommodate lower speeds, the dials required additional scales, such as a spiral with three different coloured rings within the hour symbols.’ The first ring displays speed measured over a one-kilometre distance in times ranging from 0 to 60″ (i.e., if one km is covered in 60″, the speed is 60 km/h). The second ring represents speeds measured over distances ranging from 61″ to 120″; the third from 121″ to 180″. Assume a distance of 1 km is covered in 2’5″ (or 125″: the speed is indicated by the small hand in the minute dial being on 2, and the centre seconds hand in the seconds scale being on 5). The hand in the third ring indicating the number 29 represents the speed per hour measured over a distance of one kilometre.

Spiralling tachymeter scales are useful for measuring events that occur at a rate slower than 60 cycles per hour. Longines Tachymeter Chronograph, Reference L2.780.4.18.2, and Sinn’s limited-edition Chronograph Tachymeter are both excellent contemporary examples. The latter has a central triple-graduated spiral tachymeter scale with average speeds ranging from 20 to 300 kilometres per hour.

A moving bezel with a circumferential tachymeter.

Here’s where things get really interesting – and much rarer. Surprisingly, rotating bezel tachymeters are uncommon on chronographs (and never were). Despite their scarcity, the Heuer-invented rotating-bezel tachymeter solves one of the most difficult problems that anyone faces when timing average speeds over more than one consecutive measured mile or kilometre.

The fixed tachymeter has a significant limitation in that it can only measure over a single base distance. Race timers used to use sets of three stopwatches attached to multi-sequence timing boards in the absence of rotating bezel tachymeters.

But what if the driver had to time everything himself? A flyback chronograph with a tachymeter scale was one option. But it was imprecise, inaccurate, and not always dependable. Furthermore, civilian access to flyback Chronos was limited in the 1960s and 1970s.

The (Heuer again) Taylor split-action timer was another popular solution for lap timing in the 1970s. Unfortunately, it isn’t a good tool for calculating average speeds for each mile of a drive because it lacks a tachymeter scale.

That’s about it for this blog, if you have any further clock/watches-related questions, feel free to use the comment section below. And if you want to read an interesting article on why clocks don’t appear in dreams, we have a great article on just that so do give it a click if you are interested “Why don’t clocks appear in dreams? Clocks and dreams!“. Here is also a link about the history of clocks if you want to give that a look “History of timekeeping devices

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