Already in 2015, the GMT Black paved the way for the GMT Sport. Building on this foundation, Robert Greubel and Stephen Forsey have invented and now present the result, a lightweight and ultra-strong, pro led titanium case with ovoid bezel and integrated lugs to showcase the new movement. Water- resistant to 100 meters, the new GMT Sport stands out as their most sport oriented timepiece to date. The movement was constructed from scratch – from the suspended arched bridge for the hours and minutes display, to the unique showcase of the Tourbillon 24 Secondes and the universal time display with three dimensional globe. Another truly assertive Greubel Forsey – and a revolution: the successful alliance between ergonomics, technicity and architecture.

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Strong and truly original case geometry

The completely new and original titanium case, firmly positions this new GMT in a “sports” league of its own. In their creation of this timepiece, Robert Greubel and Stephen Forsey have pushed back the limits of ergonomics and wrist comfort. They have invented a totally new case form, perfectly round from above, while revealing the accentuated arched and ovoid shape from other angles. The aerodynamics of this timepiece 4 patents are reinforced by its integrated lugs and strap resulting in distinct functional forms that perfectly fit any wrist. The sweeping satin-finished bezel with Greubel Forsey’s values relief engraved on its outer bevel, follows this unique case shape. The curved pro le of the 45 mm diameter case and ovoid sapphire crystal provide the perfect showcase for an entirely new movement architecture with an arched bridge and inclined gear train.

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Suspended three-dimensional displays

The display side of the GMT Sport presents classic Greubel Forsey architecture, an open, orchestrated theatre between suspended bridges, semi-apparent wheels and floating dials in three dimensions. In keeping with the sporting vocation of this timepiece, the focus is on legibility and eficiency. The hours and minutes are displayed by concentric openworked hands whose curved pro le follows the curvature of the case and movement. Mounted on the suspended arch centre bridge with black treated openings, the gear train literally follows the curve of the bridge, overlooking the globe to drive the hour and minute hands. Ensuring excellent visibility in the dark, the triangular tips of the arrow-shaped hands and the markers on the minute-hour-ring are enhanced with luminescent coating.

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An auxiliary dial between 10 and 11 o’clock combines the small seconds on a large rotating disc, and the second time zone display with a hand. These two coaxial displays with red triangular indexes underline this timepiece’s technicity. The 72-hour chronometric power reserve (ensured by two coaxial barrels in series) is indicated on a sector at 3 o’clock with its openworked hand and highlighted red triangle. Housed underneath the arched bridge, the power reserve differential is subtly engraved with Greubel Forsey’s values. Whether they are visible on the dial side or concealed in the caseback side, each of the 435 components of this hand-wound movement, including titanium plates and bridges, respect the most demanding criteria of the Greubel Forsey Atelier and the teams utmost concern for the finest workmanship.

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The Tourbillon 24 Secondes, the source of exceptional precision

The 24 Seconds Tourbillon is showcased at 1 o’clock secured by its distinctive and highly polished tourbillon bridge with black finished openings. This third Fundamental Invention by Greubel Forsey in the field of the tourbillon (after the Double Tourbillon 30 ° and the Quadruple Tourbillon) stands out with its cage inclined at 25 ° completing one full rotation in 24 seconds. The faster speed combined with the inventive cage inclination, significantly improves chronometric performance in a single-tourbillon system, with minimal movement height. This exclusive and patented configuration counters the disturbances induced on the movement by earth’s gravity, especially in stable positions. The rotating tourbillon cage housing the regulating organ has 88 components, for a weight of 0.38 grams – a feat made possible in particular by light alloy pillars and titanium bridges.

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A terrestrial globe showing universal time

Precision and reliability summarise Greubel Forsey’s ground-breaking GMT mechanism, presented for the first time in 2011, with the GMT Black presented in 2015. In this double-patented mechanism, the second time zone indication on the auxiliary dial between 10 and 11 o’clock is combined with a universal time display to intuitively read the current time anywhere in the world.

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The remarkable innovation and striking spectacle of the terrestrial rotating globe – seen from above the North Pole – performs each complete anticlockwise turn on its axis in 24 hours. It’s surrounded by a sapphire crystal ring with 24-hour divisions; where the wearer can read local time for all longitudes, including the day / night indicator (light zone / dark zone). On the caseback side of the GMT Sport, outer and central rings complete the sapphire cities disc to give UTC Universal and Summer Time for 24 cities in major time zones. This disc distinguishes those time zones applying summer time (on a light background) from those that do not (on a dark background). Reviewing the ergonomics, the GMT’s functions use two pushers located on the left side of the case; one to select the second time zone and the other for synchronising the local time with the globe.

The titanium and rubber crown also ensures optimum setting.

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In a sports league of its own

Created in a limited edition of 11 pieces, the GMT Sport with the key Greubel Forsey values in relief on the bezel has a black or blue rubber strap. A titanium folding clasp reinforces the comfort and ergonomics of this Greubel Forsey timepiece.

The GMT Sport, an architectural performance with augmented ergonomics, signed Greubel Forsey.

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Greubel Forsey GMT Sport

Technical specifications:

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In titanium

Limited edition

Hand-wound movement with 3 patents • Patents pending

GMT • 2nd time zone • rotating globe with universal time and day-and-night • universal time on 24 time zones • summer and winter time • cities observing summer time • GMT and Earth pushers • Tourbillon 24 Secondes • hours and minutes • small seconds • power-reserve

Movement:

Movement dimensions: Diameter: 36.90 mm • Thickness: 13.18 mm

Number of parts: Movement: 435 parts, Tourbillon cage: 88 parts, Weight of the cage: 0.38 g

Number of jewels: 63; 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

Balance wheel: Variable-inertia with gold mean-time screws (10 mm diameter)

Frequency: 21’600 vibrations/hour

Balance spring: Phillips terminal curve; Geneva-style stud

Bridges and main plate:

• Titanium

• Frosted and spotted, polished bevelling and countersinks, straight-grained flanks, black

treatment

• Multi-level, suspended-arch bridge, polished with black treatment in relief, polished bevelling and countersinks, straight-grained flanks

• Flat black polished tourbillon bridge with black treatment in relief, spotted, polished bevelling and countersinks, straight-grained flanks

Tourbillon:

• Inclined at a 25° angle, 24-seconds rotation

• Light alloy cage pillars

• Titanium cage bridges

• Gold counterweight

Gearing:

• Involute circle pro le

• Tangential inclined gear on fixed wheel and on escape wheel pinion

• Inclined gear and pro led teeth on intermediate wheels of the set-hands mechanism.

Displays:

• Hours and minutes, on suspended-arch bridge

• Small seconds on disc

• 72-hours power reserve on a sector

• 24-seconds tourbillon rotation

• Rotating titanium globe with universal time

• Day-and-night

• 2nd time zone GMT

Movement side

• 24 time zones universal time

• Summer time

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Exterior:

Case:

• Titanium with curved synthetic sapphire crystal

• Three-dimensional, variable geometry-shaped bezel with raised engraved text

• Pro led lugs, screwed fixing

• Engraved pushers

• Transparent back with high domed synthetic sapphire crystal

• Titanium security screws

• Raised engraving “GMT Sport” and “Greubel Forsey”

Case dimensions:

• Caseband diameter: 42.00 mm

• Bezel diameter: 45.00 mm

• Case height: 15.70 mm

• Height on synthetic sapphire crystals: 17.80 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 luminescent hours and minutes indexes

• GMT indicator with raised engraving

• Power-reserve indicator, engraved and lacquered

• Tourbillon rotation indicator in gold

• Rotating globe with fixed day-and-night UTC indicator in synthetic sapphire, engraved and lacquered

Movement side:

• Synthetic sapphire disc displaying city names surrounded by 2 rings (UTC engraved on the case / Summer time engraved on a gold movement plate, lacquered and hand matt-lapped)

• “Summer time” plate with limitation number, raised engraving, hand matt lapped

Hands

• Polished steel curved shape hours and minutes, with Super-LumiNova

• 2nd time zone GMT indicator, red triangle

• Small seconds, fixed red triangle

• Power-reserve indicator, in polished steel

• Aluminium 24-seconds double-tipped hand, black treatment

Strap and clasp:

• Rubber with relief text

• Titanium folding clasp, engraved GF logo

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The price for the Greubel Forsey GMT Sport is 480,000 Swiss Francs (without VAT).

For more information visit Greubel Forsey Online.