Uhrinstinkt Magazine
« Luxury watches in precision dispute »
In 729 million years, it will still run precisely to the second: The NPL-CsF2 atomic clock in London. Neither quartz watches nor mechanical timekeepers can match this precision. But which brands do you have to visit to find the most accurate mechanical watches? From Breitling to Zenith, our magazine shows you the most accurate automatic movements in the industry and explains why luck also plays a role in the purchase.
Gear deviation: measurement of precision
To determine how accurate a wristwatch is, the daily deviation from perfect time is measured. If this were zero seconds, we could speak of perfect precision and the timepiece would be a serious competitor for the NPL-CsF2 atomic clock. In reality, however, this is never the case: even quartz clocks, which are known for their exceptional accuracy, move away from atomic time by a few seconds per year. An exception are radio-controlled clocks, which do not generate permanent rate deviations due to their regular synchronization with international time signal transmitters. In the mechanical universe, however, different standards apply: top-of-the-range watches stay within the window of -2/+2 seconds daily, but even five seconds difference would be a reasonable value. In the entry-level range of mechanical watches, even 20 seconds of rate deviation per day can be tolerated. Of course, these are not the most accurate watches in the industry.
Rolex: From Datejust 41 to Submariner the strictest criteria
These days, many watch enthusiasts question whether the prices of new Rolex watches are still justified. However, there is one thing that cannot be debated: The rigorous precision standards of the traditional Geneva brand. While the COSC still allows deviations of -4/+6 seconds a day to pass in its testing procedures, watches with the five-pointed crown in their latest generation of calibers must meet -2/+2 second accuracy. The Rolex Datejust 41 was one of the first watches to enjoy the pleasure of what is currently Rolex’s most accurate self-winding 3235 movement: Thanks to a new barrel, the patented Chronergy escapement with Parachrom hairspring and other technical details, the manufacture movement is not only extremely precise, but also has a considerable power reserve of 70 hours.
Breitling, Tag Heuer and Co.: Many brands rely on COSC
Compliance with such extremely precise standards of accuracy involves a great deal of technical effort and is difficult to achieve, especially in lower price ranges. Many manufacturers from entry-level to high-end therefore rely on the standardized, globally recognized testing procedure of the official Swiss chronometer testing body COSC. Even Rolex has its watches issued the coveted certificate and additionally applies its more stringent in-house criteria. Consequently, by no means all COSC-certified timepieces are equally precise; if you’re looking for the most accurate watches, Breitling, for example, is the place to go. In addition to the in-house B01 automatic movement, the B20, developed in cooperation with Tudor and used in the Breitling Superocean Heritage II, also stands out for its accurate rate. Durable and technically balanced, it is respected throughout the industry, offering 70 hours of endurance and meeting COSC guidelines with flying colors.
In addition to the Breitling Superocean Heritage II, the TAG Heuer Carrera Caliber 36 deserves a special mention: To build the automatic movement, the Swiss manufacturer used the technical know-how of LVMH’s sister company Zenith, which has one of the most precise and best movements of all time in its program with the El Primero. Its high frequency of five hertz, which plays into the cards of a precise gait, is adopted by the TAG Heuer Carrera Caliber 36 and paired with a 50-hour power reserve. If you’re looking for the most accurate watches at relatively affordable prices, you’ve come to the right place.
Omega: METAS certificate for highest accuracy
More stringent in comparison to the COSC is the precision measurement of the Swiss Federal Institute of Metrology (METAS), which has gained a high profile primarily through Omega, but is in principle open to all brands. In order to identify the most accurate mechanical watches, METAS, in contrast to the COSC, carries out precision measurement in six instead of five layers, tests entire watches instead of pure movements, and attaches importance to a high magnetic field resistance of 15,000 gauss. Eight different tests must be completed under the influence of this magnetic field, and the watches must not deviate more than 5 seconds a day from perfect time.
A prime example of the performance of METAS movements is the caliber 8800 in the Omega Planet Ocean 600M: its free sprung balance with silicon hairspring ensures exceptional longevity and precision, while the rhodium-plated finish with Côtes de Genève arabesques is a highlight for the eye. Not to be missed is the in-house Co-Axial escapement. Despite 600 meters of water resistance, the Omega Planet Ocean manages to reveal its precise beauty through a glass back. 55 hours of power reserve is a decent value.
Zenith El Primero: King of precise chronograph movements
Zenith comes closer to the accuracy of radio-controlled watches than any other mechanical brand. Although the “normal” El Primero calibers are already extremely precise with their beat frequency of five hertz, the Defy collection breaks records with the Inventor: the technical masterpiece achieves an incredible 18 hertz (129,600 vibrations per hour) thanks to the in-house, patented Zenith Oscillator in caliber 9100, which replaces around 30 components of a standard movement in one piece. The precision of this Zenith El Primero is in heavenly spheres: A maximum of 0.3 seconds of rate deviation per day sets new standards for mechanical watches.
Variance: Why precision is a matter of luck
A glance at the precision standards of COSC, METAS and others reveals that the accuracy of mechanical watches can only ever be guaranteed within a certain range, such as -5/+5 seconds of daily rate deviation. In plain language, this means that every watch ticks a little differently, which is due not only to tiny mechanical differences, but also to the smallest differences in regulation. You have to keep in mind that one day comprises 86,400 seconds; if two watches differ by five seconds, the continuity of production is still impressive. Whether you as a buyer get a specimen close to the zero-second limit or the five-second maximum deviation is a matter of luck.
Junghans: accurate radio-controlled watches for absolute precision
Whether it’s Junghans Force or Junghans Spektrum, anyone looking for perfect precision synchronized with atomic time signal transmitters should set their sights on the radio-controlled collections from the traditional Black Forest brand. You can’t be lucky or unlucky here, because the modern radio technology achieves the same result in every watch. The all-ceramic Junghans Force is particularly modern and minimalist, while the Junghans Spektrum follows a more traditional aesthetic with Arabic numerals and a ceramic bicolor stainless steel case.
