At the Salon International de la Haute Horlogerie 2018 (SIHH), Greubel Forsey launched a new Double Balancier version in 5N red gold featuring a black gold and enamel dial.
The black gold dial with the minute circle, numerals, hour markers and power reserve in champlevé grand feu (oven-fired) enamel reveals two balance wheels connected by the constant differential. A rotation indicator fitted to the differential executes one complete turn in 4 minutes.
The three-dimensional architecture of the mechanism offers a true horological spectacle. The revolutionary Double Balancier system pushes the limits of timekeeping. Two inclined balances optimise performance in stable positions, while the Constant Spherical Differential provides more steady amplitude.
In 2009, after extensive research on multiple regulators at Greubel Forsey’s EWT (Experimental Watch Technology) Laboratory, the inclined Double Balancier was introduced as a prototype at Baselworld. It was Greubel Forsey’s 6th Fundamental Invention.
The two inclined regulating organs – then positioned on top of each other – now occupy distinct and separate three-dimensional spaces. This new configuration further develops chronometric performance while the Constant Spherical Differential cuts the timing variations in half.
Aesthetically, this timepiece is both understated and complex. A wide aperture catches the eye with powerful three-dimensional aspects, extensively revealing the heart of the mechanism. The 5N red gold hands and matching case amplify the noble appearance of this timepiece.
Technical details
Model: Greubel Forsey Double Balancier In 5N Red Gold
Movement specifications
Hand-wound movement with 2 patents
Double Balancier • hours and minutes • small seconds • 4-minutes spherical constant differential rotation • power-reserve
Movement dimensions
• Diameter: 36.40 mm
• Thickness: 8.15 mm
Number of parts
• Movement: 285 parts
• Escapement platform: 2 x 71 parts
• Spherical constant differential: 30 parts
Number of jewels
• 50
• Olived-domed jewels in gold chatons
Chronometric power reserve
• 72 hours
Barrels
• Two series-coupled fast rotating barrels (1 turn in 3.2 hours), one of which is equipped with a slipping spring to avoid excess tension
Balance wheels
• Variable-inertia with gold mean-time screws (10 mm diameter)
Frequency
• 21’600 vibrations/hour
Balance springs
• Phillips terminal curve
• Geneva-style stud
Main plates
• Nickel silver, frosted and spotted, with polished bevelling and countersinks, straight-grained flanks, grey treatment
Bridges
• Nickel silver, spotted, with polished bevelling and countersinks, straight-grained flanks, grey treatment
• Flat black polished steel differential bridges
• Flat black polished gold centre bridge, with polished bevelling and countersinks, straight-grained flanks
• 2 engraved gold plates (1x Greubel Forsey, 1x individual number)
Escapement platforms
• Inclined at a 30° angle
• Nickel silver, straight graining, hand-polished bevelling and countersinks, nickel-palladium treatment
• Polished steel pillars
• Flat black polished and barrel polished steel balance wheel bridges
Gearing
• Involute circle profile
• Inclined gear with profiled teeth on fourth wheel
Displays
• Hours and minutes
• Small seconds
• 4-minutes spherical constant differential rotation
• 72-hours power reserve on a sector
Exterior specifications
Case
In 5N red gold with convex synthetic sapphire crystal
Diameter: 43.00 mm
Height: 13.38 mm
Transparent back with synthetic sapphire crystal
Three-dimensional, variable geometry-shaped lugs
Raised polished engraving “Double Balancier” and “Greubel Forsey” on a hand-punched background
Gold security screws
Hand-polished bezel, caseband with hand-finished straight graining
Hand-engraved individual number
Water resistance: 3 atm – 30 m – 100 ft (standard NIHS 92-20/SN ISO 22810:2010)
Crown: In 5N red gold with engraved and black lacquered GF logo
Dial
Multi-level black anthracite gold dial, with engraved and “oven fired” enamelled indexes (émail grand feu champlevé)
Differential rotation and small seconds indicators in gold
Hands
Hours and minutes in polished gold, with Super-LumiNova
Small seconds, 4-minutes in polished blued steel
Power-reserve in polished gold
Strap and clasp
Hand-sewn alligator
5N red gold folding clasp, hand-engraved with the GF logo
