Hands-on Greubel Forsey GMT quad tourbillon

Greubel Forsey is a pioneer in watchmaking every year. In not a year, independent brands have not amazed us with outstanding works. One of last year’s masterpieces was Greubel Forsey GMT Quadruple Tourbillon.

Review the Greubel Forsey GMT quad tourbillon
When I visited the Basel International Watch and Jewellery Fair in 2019, I did not know what the future will bring like all of us. The actual situation prevents us from the most important observation event of the year. Many works have not even been released, and those works that have seen the light are watched by a few people. Therefore, I think I am very lucky. Even last year I had the opportunity to own the Greubel Forsey GMT Quadruple Tourbillon. I also felt very lucky. This piece is very gorgeous. In the appearance and the projects involved…

GMT timepieces have a long history under the auspices of fashion Greubel Forsey. The last one is Greubel Forsey GMT Sport, which was launched last winter. The work reviewed today was released at the 2019 Basel International Watch and Jewellery Show. With new breakthroughs in brand research and development, works continue to develop.

Those who are familiar with Greubel Forsey’s work will find that they are already familiar with the GMT quadruple tourbillon. The 46.5 mm case is made of gold (66 unique editions and 11 platinum).

The slightly curved strap is bristled in the vertical direction, while the remaining elements of the case are mirror polished. Between 8 o’clock and 9 o’clock, we found the first bump. The GMT sapphire disc and the earth are behind the curved crystal.

The right side of the case has the crown in the traditional position, and the Greenwich Mean Time (GMT) pusher is located approximately. At 4 o’clock, the second protrusion coincides with the actual time dial.

The brand logo is engraved on the crown. The words “GMT” are engraved on the front of the putter. Time-consuming engraving techniques require skill and precision.

This watch is equipped with a hand-stitched alligator leather strap and white gold folding clasp, decorated with a hand-engraved GF logo medallion.

Greubel Forsey GMT Quadruple Tourbillon (Greubel Forsey GMT quadruple tourbillon) appeared at an astonishing speed. This complex machine will even attract a complete watch agnostic. The original display is not easy to hide under the sleeve.

The watch displays the hours and minutes on the dial on the upper right. The hour and minute hands are made of polished gold and equipped with Super-LumiNova inserts. The sub-dial includes a 72-hour power reserve in a sector, and has a separate screw indicator. The hands of the power reserve are made of polished steel and are equipped with hand-polished counterbores.

The small dial at 4 o’clock shows the running seconds of polished steel, and has been treated in black called the average performance. The red hand shows Greenwich Mean Time in the second time zone.

The spectacular earth display at the bottom left of the watch shows the universal time in 24 time zones, including day and night indications.

There is a second dial on the back, which displays the world time in a fixed 24-hour system (again with day/night indication), and has a disk that displays the daylight saving time (daylight saving time) of 24 cities in light colors.

The Greubel Forsey GMT quad tourbillon is equipped with a new manual winding movement. The 805-part movement includes 4 tourbillons connected by a spherical differential. See the official drawing below.

In order to realize the watch we see today, many complicated steps need to be performed. The brand’s quadruple tourbillon watch dates back to 2008, with four parallel tourbillons juxtaposed. In 2011, the tourbillon and the position of Tourbillon 2 were invented. The mirror structure with double cages provides the viewer with a view of the top pair of hairsprings and the bottom pair of fixed wheels. Therefore, from each side of the part, you can see the head and tail view of the cage. The complexity of the mirror structure means that it also needs to reverse (mirror) rotation.

The design is complex and the execution is extremely delicate. Taking into account that each of these elements will increase its own error, that is, power-hungry houses, the 72-hour chronograph power reserve achieved by three series-connected fast-rotating barrels is amazing.

Four pairs of tourbillons (composed of two pairs) are placed on the sides of the blue planet GMT at an angle of 30°. The mirrored cages have different rotation speeds. The first cage rotates in one minute. The second upright cage performs a complete rotation in four minutes.

The tourbillon is fixed by a gold bezel, with hand-polished bevels and counter-pointing sunglasses, and light black polished bridges.

The finish is Shopping Greubel Forsey. This means the best of the best (…sir!-interpretation of Will Smith in MIB). Just look at the picture and enjoy. Of course, it is best to hold a piece in your hand.

Therefore, you can put together the technically excellent quadruple tourbillon with the gorgeous GMT. The result is a spectacle reserved for a few people. The breathtaking performance is partly divided into theater buildings and partly divided into decorations. The brand’s “surface treatment” makes watchmaking look easy. We all know (or we must) it is not that easy. Part of the workload involved was unpaid.

On my small wrist, the Greubel Forsey GMT Quadruple Tourbillon is a large but beautiful exterior. When considering comfortable parts, I usually stop at 41mm. But somehow, the “greatness” (metaphorical meaning) of this work overwhelmed the power of grasping and heaviness. In any case, if you are used to platinum or gold bracelet watches, it will not make any difference. Somehow, it feels very right on the wrist.

We need to give Cesar silver coins… This watch is an extraordinary technical achievement. The brand is actively striving to maintain traditional discount watch values ​​and technology. Please take a look at the involvement of the “Times” Foundation (Naissance d’une montre series) (Interview: David Bernard of the Time Foundation). We need to thank those who have invested money and time in this type of work. Part of the reason is technological advancement, and part of the reason is investment in traditional watchmaking.

Greubel Forsey GMT Quadruple Tourbillon Technical Specifications
Unique edition of 66 pieces, 11 pieces in white gold
Hand-wound movement with 3 patents
GMT • 2nd time zone • rotating globe with universal time and day-and-night • universal time on 24 time zones • cities observing summer time • lateral window showing the equator and southern hemisphere • GMT pusher • Quadruple Tourbillon • hours and minutes • small seconds • power-reserve

Movement dimensions

Diameter : 39.50 mm
Thickness : 13.00 mm
Number of parts

Movement : 705 parts
Four tourbillon cages : 260 parts
Total weight of the cages : 2.25 g
Spherical differential : 28 parts
Number of jewels

Olived-domed jewels in gold chatons
Chronometric power reserve

72 hours

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 (10.70 mm diameter)

21’600 vibrations/hour
Balance spring

Phillips terminal curve
Geneva-style stud
Main plate

Nickel silver, frosted and spotted with polished bevelling and countersinks, straight-grained flanks, nickel-palladium treatment

Nickel silver, frosted and spotted, polished bevelling and countersinks, straight-grained flanks, nickel-palladium 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

Involute circle profile
Conical gearing with profiled teeth

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

In white gold 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
White gold GMT pusher with raised engraving on a handpunched background
Hand-engraved individual number
Case dimensions

Diameter : 46.50 mm
Height : 17.45 mm
Water resistance of the case

Water-resistant 3 atm – 30 m – 100 ft (standard NIHS 92-20/SN ISO 22810:2010)

In white gold with engraved and black lacquered GF logo

Multi-level in gold, anthracite colour
Gold hour-ring, circular-grained with polished bevelling, black treatment
Gold hour markers
Power-reserve and GMT in gold, hand matt lapped
Small second, circular-grained

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

Hand-sewn alligator
White gold folding clasp, hand-engraved with the GF logo