Greubel Forsey GMT Balancier Convexe – The curvature of hours
Greubel Forsey has spent the better part of two decades treating the GMT complication as an open architectural problem rather than a fixed format, and the GMT Balancier Convexe, unveiled during Geneva Watch Week, is the clearest statement yet of where that thinking has landed.
The Manufacture’s original GMT, introduced in 2011, was built around a 24-second tourbillon and a case substantial enough to accommodate it. Ten years later, the Balancier Convexe replaced the tourbillon with the Atelier’s inclined balance wheel system, trading one form of mechanical theatre for another and allowing the rotating globe to move closer to the centre of the dial. This latest version continues that trajectory: the case shrinks again, from 43.5mm to 42.9mm at the caseband and from 46.5mm to 44.9mm at the bezel, while a power reserve indicator joins the dial for the first time. It is, in other words, a watch that has been getting more resolved with each iteration rather than simply more elaborate.
The rotating globe remains the watch’s organising idea. Machined in titanium with relief-engraved continents and an ocean-blue surface treatment, it turns once every 24 hours and stands in for the conventional 24-hour hand altogether, so universal time is read directly from wherever the globe happens to be facing rather than from a printed scale. A separate red triangular hand tracks the second time zone, and the two indications sit side by side rather than competing for the same visual space. Around them, the dial rises in tiers, an arrangement Greubel Forsey calls its amphitheatre construction, with hours and minutes on one level, small seconds set into its own recessed subdial, and the day-and-night indicator and new power reserve sector each given a defined position rather than folded into a shared register. The effect on the wrist is closer to looking down into a mechanism than looking at a dial, and the curved sapphire crystal, domed to a height of 17.6mm over the case, reinforces that sense of depth instead of flattening it.
Underneath the display sits a hand-wound calibre of 496 parts and 72 jewels, its escapement inclined at the Manufacture’s signature 30° angle and carried on a flat black polished and barrel-polished steel bridge, set on polished steel pillars against the titanium and nickel-silver plates. The contrast between the two metals, matte titanium against black polished steel, is doing structural work as much as decorative work, since it separates the timekeeping organ visually from the architecture that houses it. The in-house variable-inertia balance, fitted with six gold mean-time screws and beating at 21,600 vibrations per hour, sits suspended within that frame rather than tucked beneath a bridge, which is largely why the watch reads as mechanically legible even to someone unfamiliar with the calibre. Two series-coupled fast-rotating barrels, one fitted with a slipping spring to guard against excess tension, deliver the 72-hour reserve now visible on the dial, closing off what had been the one piece of practical information previously left for the owner to check elsewhere.
Colour is used with more restraint than the dial’s complexity might suggest. The blue of the globe’s oceans is echoed in the strap, in the crown’s interchangeable rubber capping, and in the treatment applied to the power reserve and small seconds bridges, so the palette reads as a single decision carried through the watch rather than a set of separate choices. Titanium does practical duty here too, keeping the case relatively light given how much is happening inside it, while the three-dimensional, variable-geometry bezel and profiled lugs are shaped to follow the wrist’s curve, a detail Greubel Forsey has been refining since the Convexe case first appeared and one that shows in how comfortably a case of this size and height actually sits.
Turn the watch over and the world-time function completes itself. A sapphire disc carries 24 reference cities, framed by two engraved and lacquered rings for standard and summer time, with a gold summer-time plate marking the current limited edition. Paris has been dropped from the list in favour of La Chaux-de-Fonds, a small substitution that puts the Manufacture’s own home on the map it uses to tell the rest of the world what time it is. Water resistance is rated to 50 metres, a figure that exists mostly as a formality on a watch built for the desk rather than the pool.
Limited to 22 pieces and priced at CHF 380,000, the GMT Balancier Convexe is not trying to be discreet, and its case depth alone means it was never going to disappear under a cuff. What it does instead is give a well-worn complication a genuinely different vantage point, treating the Earth as the display rather than as decoration around one, and building the rest of the movement as visible support for that idea rather than as a separate layer competing for attention.
Further information: https://greubelforsey.com
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