Geneva Watch Days 2025: TH Carbonspring - Tiny innovation with a big impact from TAG Heuer

At the Geneva Watch Days, the LVMH brand TAG Heuer showcased its technical side with the patented TH-Carbonspring, a carbon balance spring developed and manufactured by the TAG Heuer LAB. This surpasses conventional materials such as steel or silicon in terms of resistance to magnetic fields, shock, and wear, and increases rate stability.

The modern age of watchmaking begins with the oscillator

The history of modern mechanical watchmaking began about half a millennium ago. It took a giant leap forward in 1675, when the Dutch polymath Christian Huygens invented the modern oscillator by combining a balance wheel with a hairspring, a hair-like coil at the heart of a clockwork's regulating organ. This tiny spring enabled watchmakers to control the oscillation of a clockwork's balance wheel, significantly improving not only the precision of timekeeping but also its wearability. This ushered in the era of pocket watches and later wristwatches.

Originally made of steel, a ferrous material, it was exposed to shocks, temperature fluctuations, and magnetism. Over the last 100 years, and with the advent of the technological age, steel has been replaced by special, more resilient alloys thanks to material improvements. A quarter of a century ago, the watch industry turned to silicon, leveraging its low-maintenance and highly durable properties to significantly improve the everyday usability of mechanical watches.

Carbon in the 350th anniversary year of the modern oscillator

In the 350th anniversary year of Huygens' invention, TAG Heuer presents the heart of every mechanical watch, made of carbon. Development of the hairspring began ten years ago. After thousands of hours of testing, the technology was ready for industrialization and use in production watches.

“We have dedicated nine years of our lives to opening a new chapter in the wonderful history of precision mechanical watchmaking.”

Manuel Dupas, Technical Director of TAG Heuer

“Given the scope and complexity of the objective we set for ourselves at TAG Heuer LAB, the innovation process involved countless steps and at least as many failures as successes,” said Emmanuel Dupas, Technical Director of TAG Heuer.

"It starts with intuition, then a hypothesis, then development, and finally testing. Every result carries weight. Sometimes a result gives confidence in one's hypothesis. Sometimes it contradicts it, and the hypothesis fails. There are no shortcuts. Only hard work, supported by a healthy dose of scientific doubt and the competence of the team," Dupas continued.

The three top features of the new carbon spiral

The carbon hairspring, like Solizium, is "non-magnetic," meaning resistant to magnetism—an important feature in an age when the everyday devices around us emit strong magnetic fields. Magnetized, non-static mechanical watch components are affected and can no longer perform at their peak, which negatively impacts precision. In extreme cases, magnetized watches may stop working altogether.

Furthermore, the TH-Carbonspring is shock-resistant. Even simple movements like closing a door or clapping can cause shocks that impair the smooth running and accuracy of a mechanical watch. TAG Heuer's development counteracts these effects.

Furthermore, carbon's low weight reduces the inertia of a hairspring, thus improving chronometric performance.

"The TH-Carbonspring is a significant breakthrough in watchmaking and a milestone in the history of this 165-year-old, tirelessly innovative company," says Antoine Pin, CEO of TAG Heuer. "And this is just the beginning. Many complementary technologies are in development, and these will, over time, be reflected in our collections of high-performance, high-precision mechanical watches. This is avant-garde watchmaking for the 21st century. This is TAG Heuer."

Carrera and Monaco are the first beneficiaries of TH Carbonspring technology

For the first watches with the new TH Carbonspring technology, TAG Heuer drew on its two most famous designs: the “Monaco” and the “Carrera”.

The "Monaco Flyback Chronograph TH-Carbonspring" and the "Carrera Chronograph Tourbillon Extreme Sport TH-Carbonspring" are fittingly equipped with a carbon case and dial, while the "Carrera" also features a carbon bezel. Both timepieces are limited to €50 each.

Both dials are decorated with a spiral, hinting at the patented innovation within. The "Monaco" features the chronometer-certified automatic caliber TH20-60 with a flyback chronograph and an 80-hour power reserve.

The “Carrera” derives its precision from the automatic caliber TH20-61, a chronometer-certified chronograph tourbillon movement with a 65-hour power reserve.

(RRP €41,500 (Carrera, available from Q1/2026), €17,700 (Monaco, available from December 2025))