Greubel Forsey presents its Double Balancier Convexe watch in a new diameter of just 42.5 mm. The new Double Balancier Convexe edition will comprise only 88 timepieces, available between 2023 and 2026.
This new titanium wristwatch watch offers an unprecedentedly modern and architectural perspective of its Double Balancier movement and constant spherical differential.
The fundamental identity of Convexe collection 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.
The inaugural Double Balancier Convexe was presented in 2022. It has the emblematic double-curved case with a diameter of 43.5 mm.
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.
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.
This new Double Balancier Convexe slips more easily under a fitted sleeve. The case is made of natural titanium in a silky, luminous grey. The polished bezel features subtle satin finishes.
The lettering on the barrel cover blends seamlessly into the redesigned case. The mainplate of the movement in titanium is frosted. The same high standards apply to the bridge of each balance wheel, whose bevelling is also polished by hand.
The inclined balance wheels are linked by the Constant Spherical Differential, visible between 6 and 7 o’clock.
The 42.5 mm Double Balancier Convexe is available with a grey rubber strap or an integrated Greubel Forsey titanium bracelet.
Technical details
Model: Greubel Forsey Double Balancier Convexe 42.5 mm in Titanium, Limited edition
Movement
Hand-wound movement with 2 patents
Double Balancier, hours and minutes, small seconds, 4-minutes spherical constant differential rotation, power-reserve
Overall diameter: 37.70 mm
Thickness: 9.46 mm
Balance wheel: Variable-inertia with gold mean-time screws (10mm diameter)
Frequency: 21’600 vibrations/hour
Chronometric power reserve: 72 hours
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)
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 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, open-worked 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
Open-worked 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 case with curved synthetic sapphire crystal
Caseband diameter: 42.50 mm
Bezel diameter: 44.40 mm
Case height: 13.75mm
Height on synthetic sapphire crystals: 14.35 mm
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”
Crown: Titanium, polished, frosted and straight-grained, with GF logo
Water resistance: 10 atm – 100 m – 328 ft (standard NIHS 92-20/SN ISO 22810:2010)
Dial
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
