Robert Greubel and Stephen Forsey unveil a new timepiece showcasing a large, high precision and inclined balance wheel within a 100 metres water-resistant titanium case tailored for the most active lifestyle. The two inventor watchmakers took up the challenge of fully – and visibly – combining sport and chronometry! The unique ovoid case with ergonomic profile and integrated lugs, provides optimal protection for the movement. With this new calibre, the “Balancier S”, Greubel Forsey pursues the sporting adventure, pushing the technical limits to combine ergonomics, architecture and precision. Greubel Forsey Balancier S – A new flagship in aesthetics and performance, innovation and craftsmanship.
An avant-garde case
Robert Greubel and Stephen Forsey have been creating innovative mechanisms since 2004. Invention and creativity being two fundamental strands woven into the DNA of Greubel Forsey, with this expertise they are continuing to explore new paths of case architecture and its integration with their movement constructions. Late 2019, Robert Greubel and Stephen Forsey pioneered a new chapter with the GMT Sport – the totally new case architecture with sculptural lines combining ergonomics, robustness and comfort. Today, Greubel Forsey continues this approach, presenting a new interpretation of the unique case displaying its completely new movement. Circular from above, this case reveals the unique arched ovoid shape from other angles, features integrated lugs and strap, and a satin-finished bezel engraved with Greubel Forsey’s key values. The new “Balancier S” achieves a slim profile, reinforcing its dynamic new momentum.
The rubber crown and caseband with rubber inserts assure excellent grip and protection of the timepiece. The oval, arched sapphire crystal follows the curvature of the case. The perfect osmosis between the case and the movement is emphasized, technically and visually, by a daring double suspended arched bridge holding an inclined gear train and curved central hour and minute hands. These striking elements integrate and extend over the inclined balance wheel giving the timepiece its powerful identity, but also assuring its outstanding chronometric performance.
A focus on chronometry
The large inclined balance wheel at 7 o’clock stands out. Aiming above all to improve chronometry, it maximises the space offered by the arched case and sapphire crystal, inextricably linking form and function. In their relentless quest for precision and performance, Robert Greubel and Stephen Forsey have already challenged chronometry, notably by reinventing the tourbillon mechanism with the Tourbillon 24 Secondes, Quadruple Tourbillon and the Double Tourbillon 30°.
They chose a new approach here, based on their large balance wheel unveiled in 2016. Entirely developed and made within the Greubel Forsey Atelier, this balance wheel is distinguished by its oversized 12.6mm diameter, ensuring excellent timekeeping performance. To allow fine timekeeping adjustment of the moment of inertia, the balance wheel rim is fitted with six gold regulating screws, inset so as to limit air friction. In this new hand-wound calibre, with several patents pending, the imposing Greubel Forsey balance wheel can be seen in an inclined construction for the very first time.
This 30° angle with respect to the horizontal plane of the movement proves to be an outstanding solution for limiting timing errors due to the effects of gravity on the regulating organ (balance wheel, spring and escapement) in stable positions. Combined with the large diameter of the balance wheel and the frequency of 21,600 vibrations/hour, it provides this timepiece with excellent chronometric performance – it’s also prominently visible in action due to the unique movement architecture.
A showcase of exceptional craftsmanship
With two coaxial barrels mounted in series, the 308-component movement has a 72-hour chronometric power reserve, indicated on a sector at 2 o’clock using an openworked red-tipped hand. The central hours and minutes display, with profiled and openworked polished steel hands, is completed by a small seconds hand on the inclined plane of the escapement at 8 o’clock, accentuating the depth and relief of this new calibre. Following the Greubel Forsey creative spirit, technical and architectural innovation is accomplished with unconditional care and craftsmanship for all the components of the movement – whether these are visible through the sapphire crystal, the transparent caseback or hidden in the mechanical mysteries within. This traditional and irreplaceable artisanal know-how is mastered in the Greubel Forsey Atelier – frosting, polished bevels and countersinks, circular and straight graining highlight even the smallest surfaces. The use of titanium for the mainplate and bridges proved much more difficult for manual hand-finishing than steel or even nickel silver and further increases the technical and aesthetic challenge that this timepiece represents.
S for sport
The exceptional chronometry of this Greubel Forsey creation is combined with an unequivocally sporty case. Made of titanium and water-resistant to 100 metres, its powerful case shape is distinguished by its lightness and comfort on the wrist. Its robustness protects the movement, in particular its large balance wheel, tested in the Greubel Forsey EWT Laboratory assuring its reliability and chronometric performance at all times. The flexible and resistant rubber strap reinforces the sporty dimension, with all the comfort of a titanium folding clasp.
With the “Balancier S”, Robert Greubel and Stephen Forsey take another step in their exploration of new technical and aesthetic horizons. Rarely has a timepiece with sport-orientated characteristics displayed such chronometric performance so visibly. Rarely has a watch with a sporting vocation presented such a degree of craftsmanship in movement and case. An exclusive alliance between creativity and performance, the Art of Invention, signed Greubel Forsey.
Greubel Forsey Balancier S Technical Specifications
Balancier S Specialties
- In titanium
- Hand-wound movement
- Patents pending
- Timepiece with four hands
- Hours and minutes
- Small seconds
- Power-reserve
- 30° inclined GREUBEL FORSEY balance wheel system
Movement
- Movement dimensions
• Diameter : 37.00 mm
• Thickness : 10.62 mm - Number of parts
• Movement : 308 parts
• Escapement platform : 68 parts - Number of jewels
• 42
• 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
• 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 plate
• Titanium
• Frosted, polished bevelling and countersinks
• Multi-level, suspended-arch bridge, polished with black treatment in relief, polished bevelling and countersinks
• Movement side, frosted bridges, polished edges and bevelling
• Gold plate with engraved limitation number, circular-grained, polished bevelling and countersinks, straight-grained flanks - Escapement platform
• Inclined at a 30° angle
• Titanium, frosted, polished countersinks, large straight-grained inclined facet, black treatment
• Multi-level, titanium balance wheel bridge, polished with black treatment in relief, polished bevelling and countersinks - Gearing
• Involute circle profile
• Inclined gear and profiled teeth on intermediate wheels of the sethands mechanism and small seconds - Displays
• Hours and minutes, on suspended arch bridge
• Small seconds
• 72-hours power reserve on a sector
Exterior
- Case
• Titanium with curved synthetic sapphire crystal
• Three-dimensional, variable geometry-shaped bezel with raised engraved text
• Profiled lugs, screwed fixing
• Caseband with rubber
• Transparent back with high domed synthetic sapphire crystal
• Titanium security screws
• Raised engraving “Balancier Incliné” and “Greubel Forsey” - Case dimensions
• Caseband diameter: 43.00 mm
• Bezel diameter: 45.00 mm
• Case height: 13.75 mm
• Height on synthetic sapphire crystals: 15.60 mm - Water resistance of the case
• Water-resistant 10 atm – 100 m – 328 ft (standard NIHS 92-20/SN ISO 22810:2010) - Crown
• Titanium and rubber with GF logo
• Colour-coded rubber capping, interchangeable - Dial side
• Three-dimensional, variable geometry hour-ring, with lacquered hours and minutes indexes
• Power-reserve indicator, engraved and lacquered
• Gold small seconds dial, rhodium-coloured, polished bevel - Hands
• Hours and minutes, curved profile, polished steel
• Small seconds, red finish
• Power-reserve in polished steel, flat black polished head - Strap and clasp
• Rubber with text in relief
• Titanium folding clasp, engraved GF logo
