When an Ultra-Thin Automatic Tourbillon Withstands 5000 Gs
- Emmanuelle Festa Bianchet
- Jun 25
- 3 min read
In the secretive workshops of Haute Horlogerie, where every micron counts and engineering meets art, a quiet yet fierce pursuit has endured for decades: the creation of the ultra-thin tourbillon movement. At Bianchet, this pursuit has reached a bold new frontier, introducing a new set of challenges: the creation of an ultra-thin automatic flying tourbillon capable of withstanding real-world shocks.
The result is the Calibre UT01, a rare fusion of delicacy and resilience. A movement that stands among the most advanced and daring of its kind. What follows is the story of an engineering challenge that only a handful of watchmaking houses have dared to take on, let alone overcome.
What Defines an Ultra-Thin Automatic Movement?
To appreciate the achievement, we must first understand the challenge. In watchmaking, ultra-thin is not a stylistic expression, it’s a precise technical constraint An automatic movement is considered ultra-thin if it measures less than 4 mm in height. And in the rarified world of tourbillons, where the balance wheel is mounted inside a rotating cage, this limit becomes even more unforgiving.
Every tenth of a millimetre shaved off a 4 mm high movement increases complexity exponentially, as tolerances shrink to microscopic levels. Components must be redesigned, not simply miniaturised, to preserve mechanical integrity. Thinness must not compromise torque, amplitude, or power reserve. Nor should it limit elegance or purity of proportion, as automatic calibers are not only feats of engineering, but objects of beauty.
The Automatic Winding Conundrum
Most ultra-thin watches are manually wound. Why? Because integrating an automatic rotor, especially a central rotor, into such compact dimensions is notoriously difficult. Automatic winding systems require space not only for the rotor itself, but also for the reduction gears and reversing mechanisms that drive the mainspring.
Another key challenge is shock absorption. The added weight of the oscillating rotor amplifies the force of every impact, and sudden, violent swings can damage the movement’s most delicate components.
Enter the Tourbillon
Add a tourbillon to the equation, and the challenge escalates dramatically, both in terms of thinness and resilience. Invented in 1801, the tourbillon compensates for gravitational errors by rotating the escapement and balance wheel within a cage. The flying tourbillon, cantilevered on a single axis without an upper bridge, is inherently more delicate.
In an ultra-thin context, integrating a flying tourbillon means compressing vertical space without compromising the structural integrity of the rotating cage. This calls for re-engineering: using advanced materials, innovative stacking and kinematic principles.
Bianchet UT01: Automatic Tourbillon, Ultra-Thin and Resilient
Crafted in titanium, the Calibre UT01 measures just 3.85 mm in thickness and weighs only 8 grams. At its core: a central gold rotor and a 2.66 mm titanium flying tourbillon cage. A miniature masterpiece capable of absorbing shocks beyond 5,000 Gs.
To achieve this union of thinness and resilience, Bianchet implemented a series of technical innovations:
Suspended mainspring barrel: By eliminating the ratchet wheel, the team developed a suspended barrel system that frees vertical space while delivering a 60-hour power reserve.
Redesigned tourbillon and escapement: The 2.66 mm-thin tourbillon cage houses a large screw balance wheel, preserving visual elegance while ensuring wide functional safety margins.
Custom winding and setting mechanism: Engineered to reduce friction and optimise energy transfer.
Advanced shock protection: Absorbing elements at both the balance wheel and structural levels safeguard the movement from shocks and rotor-induced swings.
Each of these innovations represents not only a technical decision, but a philosophical one: to ensure that the UltraFino timepiece is not only refined, but wearable, durable, and ready for real-world challenges.
Field-Tested by Alexander Bublik
Months of tournament play, serves, sprints, falls, and one of the most feared double-handed backhands on the circuit. Including a quarterfinal at Roland Garros.
The UltraThin Calibre UT01 was put to the test on the wrist of professional tennis player and Bianchet ambassador Alexander Bublik. Through every rally, every point, every impact, the movement remained unshaken, precise, and perfectly reliable.
“If it can handle Bublik’s backhand, it can handle anything.” A member of the UT01 development team.
More Than a Movement. A Vision.
Beyond the technical feat, this automatic tourbillon movement embodies the emergence of a new era in ultra-thin fine watchmaking. It reflects Bianchet's vision where refinement, mechanical art, and real-world performance can coexist in harmony.
A movement built to last, ready for the real world, even at its most demanding moments.
