The third installment of our ABCs of Rolex is slightly more technical than parts one and two. That’s because today, we’re looking at Rolex movements. The calibers from the Geneva-based manufacturer are considered some of the most reliable and precise in the industry. This is in large part due to their in-house innovations like the Parachrom hairspring, Chronergy escapement, and Perpetual rotor. But what exactly do all of these components do? And what sets them apart from conventional movements? Read on to find out!
In Constant Motion: The Perpetual Rotor
Nearly every modern Rolex watch is outfitted with a so-called Perpetual rotor. While the term may sound a bit unusual, it’s actually just a simple winding rotor similar to those found in 90 percent of all automatic watches today. The operating principle behind the rotor is straightforward: A crescent-shaped rotor is mounted centrally with a weight on its outer edge. When the wearer moves his or her arm, the weight is set in motion due to the gravitational pull of the Earth. A gear transmits the resulting kinetic energy to the mainspring, which winds it. This means that if you wear your automatic watch often enough, you’ll never have to manually wind it.
Movement manufacturer Aegler developed the winding rotor in 1931. Aegler had an exclusive partnership with Rolex from the very start, and joined forces with the Genevan manufacturer in 2004. The Oyster Perpetual, the world’s first wristwatch with an automatic movement and freely oscillating rotor, was a result of the companies’ close cooperation.
Initially, the rotor could only wind the watch in one direction, but in 1959, Rolex developed a new system that was able to wind in both directions. You can recognize this system today by its red anodized reversing wheels.
Parachrom Hairspring and Microstella Screws
The balance wheel is an integral part of every mechanical watch. It is the beating heart of the movement and is responsible for its overall accuracy. Seeing as this component is so important, Rolex invested a lot of time and effort in developing its own optimized balance wheel. Rolex relies on so-called Microstella screws to finely regulate the oscillation of their balance wheels. These tiny screws are positioned inside the component and act as weights. By turning the screws, the watchmaker can adjust the inertia of the balance wheel and, thus, determine how it swings.
The balance spring is another essential part of the balance wheel. Since 2000, Rolex has been using balance springs made of their proprietary zirconium-niobium alloy Parachrom. This material is the result of more than five years of research and is particularly resistant to magnetic fields and temperature fluctuations, which means it’s more difficult to knock the balance out of sync. In 2005, Rolex introduced a new surface treatment for the hairspring, resulting in its characteristic bright blue hue.
That same year, Rolex introduced the Paraflex shock protection system. This consists of a specially shaped spring that keeps the jewel of the balance wheel securely in place, even when subjected to strong vibrations and disturbances. According to Rolex, this system improves their watches’ shock resistance by 50%.
The Parachrom hairspring is used in Rolex calibers with larger diameters, e.g., the 3235 from the Submariner Date and the 4130 from the Cosmograph Daytona. Since 2014, the balance spring of smaller movements, such as the Datejust’s 2236, is made of another innovative material, Syloxi. This material is a mix of silicon and silicon oxide and boasts similar properties to Parachrom.
The escapement is another absolutely essential component of any mechanical timepiece. The escapement works by transferring energy from the mainspring to the watch in a consistent manner. In 2016, Rolex introduced a highly efficient version of this component: namely, the Chronergy escapement.
It is a modification of the conventional Swiss lever escapement, but has some distinct advantages. For one, the components are made of a nickel-phosphorus alloy, which is resistant to magnetic fields. Rolex also managed to improve the escapement’s efficiency by 15%, meaning the energy from the mainspring is transferred to the watch more effectively. This results in an improved power reserve of up to 70 hours.
Since 2015, all Rolex watches have featured the inscription “Superlative Chronometer Officially Certified.” This is more or less Rolex’s own internal seal of approval. After their movements have passed the tests at the Swiss Chronometer Testing Institute (COSC), they undergo further in-house testing at Rolex. This time, however, the complete watch is tested rather than just the movement in isolation.
Rolex tests, among other things, the watch’s winding performance, power reserve, water resistance, and precision. To earn the title Superlative Chronometer, the watch cannot deviate from the reference time by more than +/- 2 seconds per day. This means Rolex watches are much more accurate than the standard COSC-certified chronometer, which is permitted to deviate up to -4/+6 seconds a day.
So, that rounds out part three of Chrono24’s ABCs of Rolex guide. We hope it shed some light on the mysterious world of Rolex calibers. Make sure you check out the first two installments to learn the ins and outs of Rolex materials, cases, and bracelets.