The Inside Story of TAG Heuer’s Carbon Hairspring

While we are only a few days away from the annual Baselworld exhibition show where the major watch brands launch their new collection, chances are we have already seen the most important new addition to TAG Heuer’s 2019 range. And unlike previous years, it’s not a high-tech concept watch, a mechanical watch or even a smartwatch that will steal the limelight, but instead the new carbon hairspring. “A hairspring?” you ask. How can such a small, hidden component be so important?

The humble hairspring, traditionally a flat, coiled spiral made from steel or metal alloys, plays a critical role in watchmaking, working in conjunction with the balance wheel to regulate the time keeping of mechanical watch movements.

TAG Heuer Carbon Hairspring

But while no one would dispute the importance of the hairspring in ensuring a mechanical watch actually keeps time, why has TAG Heuer chosen to focus on designing and building its own hairsprings? And why go to the trouble and expense of manufacturing from carbon rather than silicon or a metal alloy?

We wanted to go beyond the headlines of the new project, the result of which was first seen in the Carrera Nanograph, and find out more about the significance of the carbon hairspring and what it might tell us about the future. And who better to talk us through these questions than the man who led the development of the project, Guy Sémon, the CEO of the TAG Heuer Institute.


Calibre 11: What was the motivation to develop a new hairspring rather than continue to rely on existing suppliers?

Guy Sémon: We are developing and producing our own mechanical movements in-house, including plates and bridges, and we assembly our movements in our production site in Chevenez in the Swiss Jura-Mountains. Our aim is to master also the most complicated part of a watch movement, the hairspring, which we are now manufacturing at the TAG Heuer Institute in La Chaux-de-Fonds. Besides that, normal hairsprings are made of metals that include natural defects for many reasons. With our new hairspring we are solving many defects and improving the behaviour and precision of the spiral.

Calibre 11: How much of the motivation for the project goes back to Swatch Group’s sudden decision in 2012 to cut supplies of their hairspring (Nivarox) to TAG Heuer, forcing the 1887 to shift to SII (Seiko Instruments Inc) and Atokalpa?

Guy Sémon: No, the decision to produce our own spirals is not related to external suppliers. We want to improve our performances, and of course we continue to collaborate with Atokalpa.

Calibre 11: When did development start on the new hairspring and why was carbon composite chosen instead of silicon or other materials?

Guy Sémon: We started the project in 2014. There is no benefit to simply copy existing metal springs – none for customers, none in terms of performances and no reduction in costs. For silicon materials, that has been introduced to the market more than 10 years ago, big technical equipment like clean rooms etc. are required. Their main benefit is the manufacturing process but this material is fragile and is very delicate to assembly.

TAG Heuer Carbon Hairspring

Calibre 11: How does the hairspring in the Carrera Nanograph differ from the hairspring in the Zenith Defy 21 [In 2017 fellow LVMH brand Zenith launched its Defy El Primero 21 Chronograph with a Carbon-Matrix Carbon Nanotube hairsping- a project led by Semon and his team]

Guy Sémon: Defy 21 runs with two different spirals, one beating at 5 Hz for the watch certified as a chronometer, the second one is beating at 50 Hz for the Chronograph measuring 100/second.

Both spirals are made of metal Elinvar. Defy 21 doesn’t use carbon composite material, this one is dedicated to TAG Heuer only. And also to be totally clear on this topic, the material presented by Zenith at Baselworld, it was just a first proof of concept using a carbon structure but this project has been stopped. The material invented by TAG Heuer is totally different.

How challenging is it from an engineering/ cost perspective to retro-fit the TAG Heuer hairspring to existing in-house or external movements? (e.g. adding it to the Calibre 16 from Sellita?)

Guy Sémon: I don’t know if it’s challenging to design the new spiral because it results of a process set up in house to explain shortly its engineering loop starting from watch features (power reserve, frequency, space available in the watch). Taking into account these rough parameters we use a calculation tool developed in house (based on “Finit”-Elements) we get the right geometry. After we transform the shape calculated into a physical pattern made in iron atoms and “catalyst”. The manufacturing process begins in our chemical reactors “tailor made” mixing many chemical reactions at high temperature. The result is a nanotubes growing process combining with carbon infiltration. Reaching the right dimensions (time control) we put the supports containing 330 spirals in oxygen plasma atmosphere to fine-tune dimensions and then release by hand manipulation spirals ready to assembled as 100% chronometer. 

At the moment this technology has been presented only for Heuer 02 Tourbillon. Of course depending on the strategic decisions this technology can be used for any watch. 

Calibre 11: What are the main performance improvements a customer can expect from a movement with the nanograph as against the same movement with a standard Nivarox?

Guy Sémon: We don’t want to make a comparison with any trademark, given that Nivarox is a brand and not a technology, we are able to mention benefit regarding regulators using Elinvar spirals. The benefits are:

  • Very low sensitivity to gravity (1,6 grams per centimeter tube);
  • A non-magnetic material;
  • Perfect temperature compensation with the balance wheel;
  • Excellent shock absorbing performance (5000 g); and
  • Easy to assemble

Calibre 11: Will TAG Heuer supply the hairspring to other brands in the LVMH Group, or will this be exclusive to TAG Heuer? What about brands outside LVMH?

Guy Sémon: As we mentioned earlier, the technology is used at the moment at TAG Heuer only. The decision to expand the deliveries for other brands depends on LVMH decisions. We are very happy to know that prestigious brand collaborate to produce regulators. From our side, that’s already done!

TAG Heuer Carbon Hairspring

Analysis: What the Carbon Hairspring Means for the Future

TAG Heuer Carrera Heuer 02 Nanograph

To date, we have seen just one watch with the Carbon Hairspring- the Carrera Heuer 02 Nanograph shown above. But despite being showcased in a premium model, we think that the biggest impact on TAG Heuer’s range will be from the use of the Hairspring (note that we’re not calling the Hairspring “Nanograph”- we expect a new name for watches using the in-house hairspring, with “Nanograph” reserved for the Carrera shown above) in volume production watches- specifically, those with movements currently supplied by Sellita or ETA.

Adding TAG Heuer’s own high-tech hairspring to an existing Calibre 5/ 7/ 11/12/16/ 17 calibre allows premium versions of these movements to be easily produced- likely as part of upgrading the base movements to Chronometer specification. Think of these upgraded movements as bridging the gap between the true in-house Calibre Heuer 02 and the third-party movements. And it’s not just a marketing difference, as the carbon hairspring offers genuine real-world benefits for buyers.

We expect to see the first such premium watch launched at Baselworld in a few days time, which will commence a new era for TAG Heuer’s manufacture strategy. Stay tuned.


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