Greubel Forsey GMT Quadruple Tourbillon Titanium Limited Edition
The GMT Quadruple Tourbillon by Greubel Forsey is now available in a titanium version. Limited to 11 pieces, this ground breaking horological marvel incorporates new materials, new colours and new finishes.
The Quadruple Tourbillon is Greubel Forsey’s second Fundamental Invention and it averages out positional errors due to gravity in all situations, especially in stable wristwatch positions. To achieve this, the original tourbillon has been elevated to realise its full potential: inclined at 30°, doubled and then quadrupled.
The result, two synchronised Double Tourbillon 30° mechanisms, where a first cage, inclined at 30° and rotating in one minute, is nested within a second horizontal cage, completing a full rotation in four minutes. A spherical differential transmits the average timing rate of the four tourbillon cages, improving the overall chronometric performance of all the regulating organs.
The 46.5mm case of the GMT Quadruple Tourbillon is made of titanium, which is both stronger and lighter than steel, while also being extremely resistant to corrosion and magnetic fields. This exclusive limited edition in titanium with striking blue accents ensures modern and dynamic feel on the wrist.
The toughness of titanium presents a significant machining and hand finishing challenge for the components made from it, such as the GMT pusher or the folding clasp or the crown. In addition, new hand finishing details have been specially created for this timepiece.
The circular-grained hour ring with polished bevels and 72-hour chronometric power reserve indication appear for the first time in a brilliant blue. The mainplate is now frosted and spotted with polished bevelling, countersinks and straight-grained flanks, executed in a grey finish.
Set near eight o’clock, the rotating terrestrial globe in blue livery offers the simultaneous display of several different time zones: on the dial side, with a 24-hour ring around the Earth, for Day/Night indication and on the caseback side, displaying 24 major cities their respective time zones while distinguishing between those which use summer time (on a light coloured backdrop), and those which do not (on a dark backdrop).
The sapphire crystal window around the equator completes the timepiece, offering a complete view of the Earth in motion, with its continents immersed in the deep blue ocean waters, complementing the exquisite blue finish of the power reserve, hour circle and strap.
Technical details
Model: Greubel Forsey GMT Quadruple Tourbillon Titanium Limited Edition
Edition: 11 pieces in titanium
Movement
Hand-wound movement with 3 patents
Diameter: 39.50mm
Thickness: 13.00mm
Number of parts
Movement: 705 parts
Four tourbillon cages: 260 parts
Total weight of the cages: 2.25g
Spherical differential: 28 parts
Number of jewels
84
Olived-domed jewels in gold chatons
Chronometric power reserve
72 hours
Barrels
Three 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 wheel
Variable-inertia with white gold mean-time screws (10.70mm diameter)
Frequency
21’600 vibrations/hour
Balance spring
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, frosted and spotted, polished bevelling and countersinks, straight-grained flanks, grey treatment
Gold plate engraved with the individual number
Flat black polished gold plates with relief engraved text, polished bevelling and countersinks, straight-grained flanks
Four flat black polished steel tourbillon bridges, hand-polished bevelling and countersinks, straight-grained flanks
Inner tourbillons
Inclined at a 30° angle, 1 rotation per minute
Outer tourbillons
1 rotation in 4 minutes
Hand-bevelled and open-worked cage pillars
1 gold counterweight per double cage bearing the individual number of the timepiece
Gearing
Involute circle profile
Conical gearing with profiled teeth
Displays
Hours and minutes
Small seconds (mean performance)
72-hours power reserve on a sector
2nd time zone GMT
24 time zones universal time
Rotating titanium globe with universal time
Cities observing summer time
Day-and-night
Exterior
Case
In titanium with asymmetrical convex synthetic sapphire crystal
Transparent back with asymmetrical convex synthetic sapphire crystal
Lateral window with shaped synthetic sapphire crystal
Three-dimensional, variable geometry-shaped lugs
Raised polished engraving “GMT Quadruple” and “Greubel Forsey” on a hand-punched background
Gold security screws
Polished bezel, caseband with hand-finished straight graining
Titanium GMT pusher with raised engraving on a hand-punched background
Engraved individual number
Case dimensions
Diameter: 46.50mm
Height: 17.45mm
Water resistance of the case
Water-resistant 3atm – 30m – 100ft (standard NIHS 92-20/SN ISO 22810:2010)
Crown
In titanium with engraved GF logo
Dial
Multi-level in gold, anthracite colour
Gold hour-ring and power reserve, circular-grained with polished bevelling, blue treatment
Gold hour markers
GMT in gold, hand matt lapped
Small second, circular-grained
Hands
Hours and minutes in polished gold, with Super-LumiNova
Small seconds in polished steel, black treatment
Power-reserve in polished steel, hand-polished countersink
2nd time zone GMT indicator, red
Strap and clasp
Rubber or hand-sewn alligator
Titanium folding clasp, engraved with the GF logo
