Greubel Forsey presents the Balancier Convexe S² and the Double Balancier Convexe in slimmer case diameters. In creating more compact timepieces while preserving the harmony of their proportions and the architectural requirements of the movement, we reviewed the construction of these two calibres. The 41.5 mm Balancier Convexe S² and the 42.5 mm Double Balancier Convexe will be limited and only be available between 2023 and 2026.
Double Balancier Convexe in titanium 42.5 mm
Greubel Forsey unveils its Double Balancier Convexe in a new diameter of just 42.5 mm. This new creation, in titanium, will be made as a limited edition of only 88 pieces and offers an unprecedentedly modern and architectural perspective of its Double Balancier movement and constant spherical differential.
The popular belief is that a watchmaking company produces its movements, then its cases, for which it defines the diameter that it feels best meets its customers’ expectations. Nothing could be further from the truth at Greubel Forsey. At the Atelier Manufacture, each timepiece is designed exclusively following the principle of unique creative process, “one calibre – one case”. They are inseparable. They are created for each other, from the first sketch to the final assembly.
This is particularly true of the Convexe collection. Its fundamental identity is based on the distinctive architecture of its double-curved case, which hugs the wrist perfectly. Its design evokes the construction of the movement that unfolds in three dimensions and emphasises its profile.
A very limited inaugural series
The guiding idea behind this new diameter is, once again, to push back the limits, even those already set by Greubel Forsey: how to create a more compact timepiece while preserving the harmony of its proportions and the architectural requirements of the movement.
To meet this challenge, Greubel Forsey had to rethink the construction of the movement and enhance its finish – only possible thanks to the high level of expertise at the Greubel Forsey workshops, where each timepiece is entirely assembled and finished by hand. This allows the Atelier’s artisans to adapt their art, piece by piece, according to the specifics of each collection. The 42.5 mm Double Balancier Convexe edition will comprise only 88 timepieces, available between 2023 and 2026.
In-depth work
The inaugural Double Balancier Convexe was presented in 2022 and was not then designed for a diameter of 42.5 mm. Underlining the disruptive nature of this creation, this reduction in diameter is particularly significant, taking note that the tolerances of a Greubel Forsey timepiece are adjusted to the micron. Averted collectors will fully appreciate this fact.
The smaller volume of the new 42.5 mm-diameter case houses the Double Balancier, the sixth Fundamental Invention from Greubel Forsey. Its prototype, patented in 2007, has continued to evolve ever since. It was first offered as an EWT (Experimental Watch Technology) prototype, in which the two regulating organs were superimposed and inclined at 20°. A second evolution of six pieces followed close behind, with the two regulating organs positioned on three-dimensional and inclined planes, this time at 35°. In 2016, Greubel Forsey presented the Double Balancier movement in its current form: the two balance wheels, both inclined at 30°, optimise performance, especially in stabilised positions, while the Constant Spherical Differential generates greater amplitude stability.
Preserving lines and comfort
Its new 42.5 mm diameter makes it possible to approach the Convexe case with a new configuration. Mathematically, with a smaller diameter, its curves should have been steeper. But the Greubel Forsey teams have reworked the convex profile, which is unique in the world, adapting its precise angles and proportions, rather than simple homothety. The new case has been completely redesigned to provide optimum comfort on the wrist and maintaining Greubel Forsey’s own expectations for ergonomics and excellence.
The result is an extremely comfortable timepiece with a more discreet silhouette that is resolutely harmonious. It’s an original design, eagerly awaited by collectors, and one that the Atelier took enormous care to refine to its renowned level of perfection.
New profile, new finishes
This new Double Balancier Convexe slips more easily under a fitted sleeve or can be worn casually on a bare wrist. Depending on their preference, collectors can hide or reveal the mechanics of the movement, without appearing ostentatious.
The finishing of this timepiece has been designed with this in mind. The case is made of natural titanium in a silky, luminous grey. The polished bezel features subtle satin finishes, contrasting shine and elegance through the plays of light so characteristic of the Convexe line. The lettering on the barrel cover blends seamlessly into the redesigned case while its new design creates an exclusive dynamic that evokes it rotating and simultaneously delivering 72 hours of chronometric power reserve.
The mainplate, also in titanium, is frosted – again, discerning collectors will note the ambition of this finish, titanium being a tenacious natural material and therefore by definition the most difficult on which to apply frosting. The same high standards apply to the bridge of each balance wheel, whose bevelling is also polished by hand – a particularly meticulous exercise requiring exceptional expertise, especially when the bridge in question is openworked and flat black-polished.
The inclined balance wheels are linked by the Constant Spherical Differential, visible between 6 and 7 o’clock. In 4-minute sequences, it delivers the best running average to meet the performance, precision, and reliability requirements that Greubel Forsey imposes on all its timepieces.
Available from June 2023, the 42.5 mm Double Balancier Convexe will be offered with a grey rubber strap or an integrated Greubel Forsey titanium bracelet.
Balancier Convexe S2 in titanium 41.5 mm
Presenting the Balancier Convexe S2 in a diameter of 41.5 mm. Available in grey or blue, the watch is a veritable urban landscape, highly architectural and with ultra-fine contrasting lines, showcased within an unprecedented size where technology and aesthetics rival in boldness.
2021: an unexpected creation crosses the skies over Dubai, where it is unveiled. Its name: Balancier Convexe S2. Greubel Forsey is building a collection with strong, modern, innovative and architectural identities. The Balancier Convexe S2 is the first manifestation of this.
The timepiece maintains continuity with its heritage and stands out through more refined and innovative perspectives. This exquisite calibre is now available in two editions, each in a brand new 41.5 mm case.
An iconic profile
The Balancier Convexe S2 showcases its famous Convexe profile. Since its introduction in 2019, this case profile has won over collectors for its comfort and cutting-edge ergonomics. The entire case is double-curved, both front and back. On the back, it offers total comfort, hugging the curve of the wrist. On the front, the convex profile of the bezel plunges along the vertical axis of the timepiece, at both 12 and 6 o’clock. This dynamic form delivers the promise of infinite creative possibilities.
Along the 12 and 6 o’clock axis, the hour-ring drops away beneath the sapphire crystal revealing an unprecedented open space below the glass. Greubel Forsey has made full use of it: the lower quarter of the timepiece prominently features the collection’s signature large balance wheel. Taking full advantage of the space available, it is inclined at 30°, as if suspended from the straight-grained, openworked bridge with its hand-polished bevelling.
Time at your fingertips
In the apex, by contrast, the hour-ring is at its highest possible to the sapphire crystal. Enhanced in luminescent white, the hour and minute hands have never appeared so high. They almost seem to make contact with the glass, giving the illusion of being able to touch the time. Here again, we find the double openworked “arch bridge” with suspended wheels, whose architecture reveals the movement’s patented mechanics. Bridges, elevations, levels, contrasts, relief, vanishing lines: the piece is clearly inspired by a city, one of those contemporary metropolis explored by Greubel Forsey collectors, between skyline and waterfront.
Skyline and waterfront
Both could be the inspiration for the two versions of the timepiece. In the first, multiple shades of grey recall urban architecture. Greubel Forsey deploys a wide range of finishes to magnify the slightest chromatic variation, from frosted plates to straight-grained and mirror-polished surfaces. An isolated coloured zone stands out for the power reserve, with an arrow pointing towards the 72 hours chronometric precision.
In the blue version, Greubel Forsey plays with direct contrast. With a light-coloured mainplate, a midnight-blue hour-ring and elevated luminescent hour-markers standing out, the large balance and small seconds at 8 o’clock revealed on the inclined surface, the composition is as soft as it is contrasting.
Pure Greubel Forsey
For the first time, this urban landscape is housed in a smaller, slimmer case. Thanks to its honed proportions, the case is just 41.5 mm in diameter. A smaller, and therefore lighter timepiece, cut for everyday use from a block of titanium to wear either on a textile-style textured rubber strap or a full titanium bracelet. However, a simple homothety of the original construction to bring it to 41.5 mm wouldn’t have worked. Greubel Forsey, therefore, completely reworked this Balancier Convexe S2 while preserving all the codes.
First: to ensure that the new diameter of the case did not pronounce the curves, the profile had to be perfected on both the dial side (to adapt to the new calibre) and the caseback side (to preserve the curvature that matches the shape of the wrist).
Secondly, the movement has been considerably refined. Here, on the technical side, the architecture has been rethought to maximise the reduced space. The aim was to maintain coherent proportions between the movement and the volume imposed by the new 41.5 mm case. The aesthetics and finishing have also been adapted to ensure that they continue to stand out in this new environment.
The texts and unique design of the barrel cover blend seamlessly into the redesigned case. This creates an exclusive dynamic that evokes its rotation, ensuring a 72-hour chronometric power reserve, and a display which is also perfectly integrated and contributes to the overall harmony inspired by this original 41.5 mm timepiece.
The new 41.5 mm Balancier Convexe S2 in titanium will be produced as only 88 pieces of each version from 2023.
Double Balancier Convexe
Limited edition
Hand-wound movement with 2 patents
Double Balancier • hours and minutes • small seconds • 4-minutes spherical constant differential rotation • power-reserve
Movement
Movement dimensions
• Overall diameter: 37.70 mm
• Thickness: 9.46 mm
Number of parts
• Movement: 371 parts
• Escapement platform: 2 x 70 parts
• Spherical constant differential: 30 parts
Number of jewels
• 50
• Olived-domed jewels in gold chatons
Chronometric power reserve
• 72 hours
Barrels
• Two coaxial series-coupled fast-rotating barrels (1 turn in 3.2 hours), one of which is equipped with a slipping spring to avoid excess tension
• Relief-engraved text, circular-grained, black treatment, polished chamfer
Balance wheel
• Variable-inertia with gold mean-time screws
(10mm diameter)
Frequency
• 21’600 vibrations/hour
Balance springs
• Phillips terminal curve
• Geneva-style stud
• Anti-shock system with gold pin
Bridges and main plates
• Titanium
• Frosted, polished bevelling and countersinks, grey treatment
• Multi-level, openworked centre bridge, polished bevelling and countersinks
Movement side
• Flat black polished steel differential bridge
• Gold plate with engraved limitation number, circular-grained, polished bevelling and countersinks, straight-grained flanks
Escapement platforms
• Inclined at a 30° angle
• Steel, straight graining, hand-polished bevelling and countersinks
• Polished steel pillars
• Openworked steel balance wheel bridges, hand-polished bevelling and countersinks, flat black polished
Gearing
• Involute circle profile
• Inclined gear with profiled teeth on fourth wheel
Displays
• Hours and minutes
• Small seconds
• 4-minutes spherical constant differential rotation
• Power reserve on a sector
Exterior
Case
• Titanium with curved synthetic sapphire crystal
• Three-dimensional, variable geometry-shaped bezel, hand-polished with hand-finished straight graining
• Profiled lugs, screwed fixing
• Transparent back with curved synthetic sapphire crystal
• Titanium security screws
• Raised engraving “Double Balancier” and “Greubel Forsey”
Case dimensions
• Caseband diameter: 42.50 mm
• Bezel diameter: 44.40 mm
• Case height: 13.75mm
• Height on synthetic sapphire crystals: 14.35 mm
Water resistance of the case
• Water-resistant 10 atm – 100 m – 328 ft
(standard NIHS 92-20/SN ISO 22810:2010)
Crown
• Titanium, polished, frosted and straight-grained, with GF logo
Dial side
• Three-dimensional, variable geometry hour-ring with engraved and lacquered minute-circle
• Three-dimensional, variable geometry hour indexes, polished, with Super-Luminova
• Power-reserve indicator, engraved and lacquered
• Differential rotation and small seconds indicators in gold
Hands
• Hours and minutes, curved profile, polished steel with Super-Luminova
• Power-reserve, 4-minutes and small seconds in polished steel, blued according to the version, flat black polished head
Strap and clasp
• Non-animal material, rubber with texture in relief, titanium folding clasp, engraved GF logo
• On demand: 3-row metal bracelet in titanium, folding clasp with integrated fine adjustment, engraved GF logo
Balancier Convexe S2
Limited edition
Hand-wound movement • Patents pending
Hours and minutes • small seconds • power-reserve • 30° inclined Greubel Forsey balance wheel system
Movement
Movement dimensions
• Overall diameter: 37.00 mm
• Thickness: 10.05 mm
Number of parts
• Movement: 301 parts
• Escapement platform: 68 parts
Number of jewels
• 43
• Olived-domed jewels in gold chatons
Chronometric power reserve
• 72 hours
Barrels
• Two coaxial series-coupled fast-rotating barrels (1 turn in 3.2 hours), one of which is equipped with a slipping spring to avoid excess tension
• Relief-engraved text, circular-grained, black treatment
Balance wheel
• In-house variable-inertia with 6 gold mean-time screws (12.60 mm diameter)
Frequency
• 21’600 vibrations/hour
Balance spring
• Phillips terminal curve
• Geneva-style stud
Bridges and main plates
• Titanium
• Frosted, polished bevelling and countersinks, anthracite or blue treatment according to the version
• Multi-level, openworked suspended-arch bridge, black treatment, straight-grained and polished, polished bevelling and countersinks
Movement side
• Frosted bridges, polished edges and levelling
• Gold plate with engraved limitation number, circular-grained, polished bevelling and countersinks, straight-grained flanks
Escapement platform
• Titanium
• Inclined at a 30° angle
• Frosted, polished countersinks, large straight-grained inclined facet
• Multi-level, openworked balance wheel bridge, straight-grained and polished, polished bevelling and countersinks
Gearing
• Involute circle profile
• Inclined gear and profiled teeth on intermediate wheels of the set hands mechanism and small seconds
Displays
• Hours and minutes, on suspended arch bridge
• Small seconds
• Power reserve on a sector
Exterior
Case
• Titanium with curved synthetic sapphire crystal
• Three-dimensional, variable geometry-shaped bezel, hand-polished with hand-finished straight graining
• Profiled lugs, screwed fixing
• Transparent back with high domed synthetic sapphire crystal
• Titanium security screws
• Raised engraving “Balancier Incliné” and “Greubel Forsey”
Case dimensions
• Caseband diameter: 41.50 mm
• Bezel diameter: 44.00 mm
• Case height: 12.85 mm
• Height on synthetic sapphire crystals: 14.80 mm
Water resistance of the case
• Water-resistant 10 atm – 100 m – 328 ft (standard NIHS 92-20/SN ISO 22810:2010)
Crown
• Titanium, polished, frosted and straight-grained, with GF logo
Dial side
• Three-dimensional, variable geometry hour-ring, polished, with engraved and lacquered minute-circle
• Three-dimensional, variable geometry hour indexes, polished, with Super-Luminova
• Power-reserve indicator, engraved and lacquered
• Gold small seconds dial with polished bevel
Hands
• Hours and minutes, curved profile, polished steel with Super-Luminova
• Small seconds, in polished steel, flat black polished head
• Power-reserve, red triangle
Strap and clasp
• Non-animal material, rubber with texture in relief, titanium folding clasp, engraved GF logo
• On demand: 3-row metal bracelet in titanium, folding clasp with integrated fine adjustment, engraved GF logo
GREUBEL FORSEY
Greubel Forsey has been constantly striving for excellence since its founding in 2004 and is active at the very top of the high-end watchmaking pyramid, creating timepieces renowned for their exceptional quality. Located in La Chaux-de-Fonds (Switzerland), the Atelier Manufacture brings together remarkable expertise, exceptional innovation and rare excellence in fine craftsmanship. Greubel Forsey has made the “Art of Invention” its guiding principle: since its creation, the signature brand has imagined, patented and created 7 Fundamental Inventions that have radically changed the world of fine watchmaking. All Greubel Forsey timepieces adhere to 5 principles: invention and innovation; hand-finishing and hand watchmaking; performance and reliability; architecture and design; rarity and exclusivity. By refusing to compromise, the signature brand has established itself in just a few years as one of the finest names in technical and contemporary fine watchmaking. Now approaching its 20th anniversary, Greubel Forsey is completely independent and has embarked on a fundamental transformation from an inventive workshop to a fully-fledged watch brand.