11 January 2023


By In General, Rolex, Technical

You may read on watchmaking forums or on social media that Rolex movements are not technologically innovative and Rolex is a brand that does not push forward with the innovation game. Well, there may be some truth in these statements, but they represent an incomplete vision of the topic. 

Rolex philosophy has always been focused on evolution rather than revolution and you’ll simply never find an extremely complicated watch among the Rolex catalogue. In fact, today’s Rolex models still look quite similar to their ancestors, but what’s hiding behind them?

Let’s first start from the basics and recalling the evolution of the main Rolex mechanics. One of the most famous innovation introduced by Rolex is for sure the first waterproof watch (the Oyster) which was followed some years later by the perpetual rotor. Then, they introduced the first watch to display a date in a window (the Datejust) and to display the entire weekday (the Daydate). In 1954, considering PanAm specific request, Rolex invented the GMT to track a second time zone and in 1960 they developed, together with Doxa, the helium escape valve. We have to admit that Rolex inventions resulted to be the basis for what we consider the modern watch scene. How many watches feature a GMT complication, a helium escape valve or display the date in a window nowadays?
However, the most interesting developments introduced by Rolex should be found elsewhere, inside the movements. Indeed, Rolex is able to guarantee incredible caliber performances, such as an accuracy of +2/-2 seconds per day and a recommended service interval of ten years. How is this even possible?

Rolex focused and is still focusing its attention on the reliability and precision of the calibers and the following three components result to have a crucial importance to achieve the mentioned results: 

  • Balance wheel
  • Shock absorber
  • Escapement
Wheel train – photo courtesy of fratellowatches.com

Balance wheel

The heart of every Rolex watch consists of the balance wheel with variable inertia that is equipped with micro-star nuts able to guarantee high-precision regulations and offer great stability. Together with the hairspring, it constitutes the oscillator and it represents the most important part of a watch since it is in charge of keeping the time accurately. Thus, Rolex pays a lot of attention to this organ. 

Keeping a tolerance of one second per day is equivalent to have a deviation of one centimeter over one kilometer and such precision can be archived by minimizing the environmental effects on the watch, like temperature changes, shocks and magnetic interference. The few materials that show the properties needed to manufacture hairsprings (such as iron-, nickel-, cobalt- and chrome-based ferromagnetic alloys) can provide great stability from temperature changes but not as much for magnetic and shock resistances. The solution to this problem is called Parachrom, a material used to manufacture the hairspring crafted from a paramagnetic alloy of niobium, zirconium and oxygen, and it took five years of research to develop and later patent. This peculiar alloy is unaffected by magnetic fields and it is up to ten times more resilient to shocks than traditional hairsprings, offering great stability over temperature variations and overcoming the weaknesses of ferromagnetic components. The overall research on Parachrom resulted in two patents: one for the chemical composition of the alloy and another for the surface treatment process which gives the Parachrom hairspring its distinctive blue color and reinforces its long-term stability. Moreover, Rolex developed its own processes and technologies to produce hairsprings guaranteeing independence from third-party suppliers and precise qualitycontrol, being one of the few brands to be able to produce its own hairsprings.

Parachrom hairspring – photo courtesy of Rolex.com

Shock absorber

As introduced before, to keep the precision during the lifespan of a watch it is necessary to have a strong shock resistance. Thus, Rolex, as well as other watch manufacturers, fitted all movements with shock absorbers, but this tiny component has its intrinsic limits. The ruby clip may be insufficiently resistant and can open in the event of a sudden shock, resulting in an immediate movement stop. To overcome these limits, Rolex engineers developed a system that increased the shock-resistance of this peculiar component by 50% while preserving the chronometric properties of the balance wheel through an innovative geometry, which allows the shock absorber to withstand extremely demanding conditions. It was patented in 2005 under the name of Paraflex and it ensures the ruby to remain firmly positioned and with no risk of any deformation of the structure.

Paraflex shock absorber – photo courtesy of Rolex.com


The third main component that strongly contributes to the watch precision is the escapement, the organ that receives and regulates the energy from the mainspring, transmitting it to the oscillator and determining the division of time. Without the elements that constitutes it, the mainspring would simply unwind in one go and release all the energy stored when winded. Simultaneously, the escapement keeps the momentum of the hairspring and balance wheel preventing the watch from stopping. The escapement consists of four components: the escape wheel, the pallet fork, the pallet bridge (which holds the pallet fork in place by limiting its movements via integrated banking pins) and, finally, the roller with its ruby impulse pin fixed on the oscillator staff. Working as a chain, from the escape wheel to the pallet fork and to the roller, this assembly of components is subject to major mechanical stresses and its efficiency is key for the performance of the movement. Some parts are made of synthetic rubies, to minimize friction with the metal, such as the pallet stones, the impulse pin on the table roller and the bearings. The contact surfaces, in particular those on the escape wheel teeth, must be perfectly smooth and polished since reducing friction and increasing efficiency is the key to prevent energy loss to better exploit the power reserve, as generally less than 40 per cent of the mainspring’s energy reaches the oscillator.

To increase the efficiency of its escapements, Rolex has developed and patented an evolution of the traditional Swiss lever escapement. This optimized escapement, named Chronergy, is the result of extensive research that led to a new design of the pallet fork and escape wheel. These two redesigned components are made of nickel-phosphorus, an alloy that makes them resistant to magnetic interference. In the new design the anchor and the balance wheel are not aligned as in the traditional Swiss anchor escapement but present a greater distance to create a greater leverage effect. Moreover, since the whole train has to start and stop for every beat, the escape wheel is lighter showing lower the inertia and hence higher efficiency. To archive a reduction in weight the escape wheel has a cut-out design. Thanks to this innovative geometry, the efficiency of the escapement is improved by 15% while continuing to provide optimum reliability and resistance.

Chronergy escapement – photo courtesy of watchesbysjx.com


Rolex is often described as a brand that does not pursue technical innovation and whose movements are not comparable to the competitors. From what we have seen in the previous sections, the combination of all the mentioned inventions brings contemporary Rolex movement at the forefront of the state of the art for mechanical watches reaching matchless performance being the only brand that can guarantee an accuracy of +2/-2 seconds per day. Furthermore, Rolex allows its movements to be extremely reliable, hence bringing the service interval up to ten years. Rolex today really deserves to be recognized as an industrial watch brand that can deliver the most precise and reliable watches on the market.

Written by Giovanni Andrean

Born in 1999, energy engineer and truly passionate about watches since he was a teenager. He is attracted from the mechanical marvel of watches and their strong heritage in the same way one could be attracted by a piece of art.