Greubel Forsey the Quadruple Tourbillon Secret in 5N Red Gold
A Unique Edition of eight timepieces in 5N red gold
With its full dial concealing the intricate ballet of a quartet of tourbillons below, the Quadruple Tourbillon Secret offers the ultimate in discretion and refinement. Behind the blackened gold dial. An exceptional movement with superlative fine finishing features two double tourbillon systems linked by a spherical differential playing out a micro-mechanical ballet. Hinted at by the sub-dial indications, but visible only through the lateral window on the case band and through the display back.
While the 18k gold skeletonised hour and minute hands, GF logo, applied 12, hour indexes and individually numbered plate first attract the eye due to their high-contrast juxtaposition against the blackened gold background, it is the two lower sub-dials –the one at 7 o’clock doubles as a bridge − covering the double tourbillons that hint at the complexities below.
The larger small seconds dial near 7/8 o’clock shows 240 seconds, which is the 4-minute rotation of the outer double tourbillon cage, while the small seconds at 5 o’clock indicates the 4-minute rotation of the second double tourbillon cage. A high-performance spherical differential links the two double tourbillon systems and supplies an average rate to the gear train. Small seconds with the sectorial power reserve indicator at 2 o’clock displays the averaged rate of the two inclined balance wheel oscillators.
With its precision choreography artfully concealed, the Quadruple Tourbillon Secret represents a special personal link for the collector with Robert Greubel and Stephen Forsey. Exclusivity is assured by a unique edition of eight pieces in 5N red gold and eight pieces in platinum.
The movement comprises 519 components, 261 of which make up the four tourbillon cages, it is powered by two mainspring barrels which provide an optimal power reserve of 50 hours. The oscillators feature variable inertia balance wheels, Phillips terminal curves and beat at 3Hz/21,600 vibrations per hour.
The plates and bridges are in nickel silver finished in nickel-palladium with hand polished bevels, spotted and straight-grained finishes and. The main dial is in blackened or silvered gold with applied indices. The case is available in platinum 950 or 5N red gold and measures 43.5 mm in diameter by 16.11 mm high and features asymmetrical domed synthetic sapphire crystals on the dial side and for the display back. The black alligator strap is hand stitched with a folding clasp in platinum 950 or 5N red gold to complement the case.
The Quadruple Tourbillon was Greubel Forsey's second Fundamental Invention and features four tourbillons – composed of two Double Tourbillon 30° systems – working independently in pairs and linked by a spherical differential that transmits the average of their rates to the gear train and time display. In this world-premiere construction, the double tourbillons with their separate 30° inclined balances, which are generally on completely different planes, average-out gravity-induced errors on the balance and spring oscillator, to improve timekeeping. This construction allows for superior chronometric performance for a minimum volume/maximum balance diameter ratio.
The two double tourbillons regulators are linked by a spherical differential that transmits the average of their rates to the gear train and indications. While flat differentials are a regular feature of timepieces (usually in conjunction with power reserve indicators), spherical differentials (like those used in cars) are extremely rare due to the difficulty of manufacturing their complex components.
Fine Finishing and Aesthetics
As with all GreubelForsey timepieces, the level of hand-finishing and decoration throughout the Quadruple Tourbillon Secret is without compromise. Movement components are designed with forms that bring out their beauty to maximum effect, offering myriad sublime details to be discovered and esteemed. Frosted plates, blackflat polished steel and stunning hand-polished bevels with sharp internal angles (which machines cannot do as well as a highly experienced hand) bring unparalleled vivacity. Large jewels set in polished gold chatons, and mirror-polished screws provide evidence of the extremely high quality that pervades every aspect of this timepiece.
Quadruple tourbillon à différentiel sphérique
Thanks to this uncompromising creation, Robert Greubel and Stephen Forsey have reaffirmed themselves as authentic inventors, using the mechanical timepiece as their means of expression.
The Quadruple Tourbillon à Différentiel is a blend of art and technical innovation which encapsulates the very soul of its the two creators.
Robert Greubel and Stephen Forsey have engineered the four Tourbillons together in a contemporary design, in which elegance and harmony are the dominant features.
In the same spirit, and owing to the impressive number of parts which make up the movement, an asymmetrically-shaped case was chosen. The asymmetrical form was also an aesthetic tribute to the asynchronicity of the four Tourbillons.
With its sophisticated coalescence of technical Invention and artistic design, the Quadruple Tourbillon à Différentiel encapsulates the best in fine watchmaking.
Wearing a Quadruple Tourbillon à Différentiel is to enter the universe of Robert Greubel and Stephen Forsey, and to share, appreciate and be empathetic to the essential values emanating from their Invention.
ex. : Model Quadruple Tourbillon
In the Secret version, the tourbillon cage is turned upside down, so the construction of the movement is a little bit different. This was done as, being the two tourbillon cages, visible only from the case back, you can see on one cage the top and on the other the bottom of the tourbillon cages.
Quadruple Tourbillon Secret
Unique edition of 8 pieces in platinum / 5N red gold
Mechanical hand-wound movement, Calibre GF03j
Quadruple Tourbillon • power-reserve indicator• hour and minute display • small second • 4-minute outertourbillon rotation indicators
Movement with patented tourbillons
- Diameter: 36.40 mm
- Thickness: 9.85 mm
Number of parts
- Complete movement: 519 parts
- 4 tourbillon cages: 261 parts
- Total weight of the cages: 2.35 g
- Spherical diff erential: 28 parts
Number of jewels
- Olived-domed jewels in gold chatons
Power reserve : 50 hours
- Rapid rotating twin barrels (1 turn in 3.2 hours) one of which is equipped with a slipping spring to avoid excess tension
- Free sprung variable-inertia balance with white gold mean-time screws (10.70 mm diameter)
Frequency : 21’600 vibrations/hour
- Phillips terminal curve
- Geneva-style stud
- Nickel silver, spotted with polished bevelling, straight-grained fl anks, nickel-palladium treatment
- Nickel silver, frosted, spotted with polished bevelling, nickel-palladium treatment
- Gold plate engraved with the individual number
- Two steel tourbillon bridges (movement side): hand-bevelled, fl at black polished with polished countersinks
- Two nickel silver tourbillon bridges (dial side)
- Involute circle profi le
- Conical gearing with corrected profi les
- Inclined at a 30° angle, 1 rotation per minute
- 1 rotation in 4 minutes
- Hand-bevelled and openworked cage pillars
- 1 gold counterweight per double cage
- Hour and minute
- Small second (mean performance)
- 50-hour power reserve on a sector
- 4-minute outer-tourbillon rotation indicators
- 18k 5N red gold or platinum 950 with asymmetrical convex sapphire crystal
- Transparent back with asymmetrical convex sapphire crystal
- Lateral window with shaped sapphire crystal
- Three-dimensional, variable geometry-shaped lugs
- Gold security screws
- Polished bezel and centre band with hand-fi nished straight graining
- Hand-engraved individual number
- Raised polished engraving “Quadruple” on a hand-punched background
- Unique edition of 8 pieces in 5N red gold or platinum
- Diameter: 43.50 mm
- Thickness: 16.11 mm
Water resistance of the case : 3 atm - 30 m - 100 ft
- In 5N red gold or platinum with engraved and black lacquered GF logo
• Black dial (5N red gold version) or silvered dial (platinium version)
• Gold hour markers
• Gold display sectors
• Applied gold GF logo
- 5N red gold
- Hour and minute and small second in polished gold
- 4-minute and power-reserve in polished steel
- Platinium version
- Hour and minute and small second in black steel
- 4-minute and power-reserve in polished gold
- Hour and minute and small second in black steel
Strap and clasp
- Hand-sewn black alligator
- 18k 5N red gold or Platinum 950 folding clasp, hand-engraved with the Greubel Forsey logo