Geneva Watch Days 2023: Greubel Forsey Unveils New Convexe Models in Carbon

Greubel Forsey watches have always been something of an acquired taste, as they embody a penchant for higher excellencies in all aspects of watchmaking. It is something no one ever possesses without long cultivation, great labor in exposition and attention on the part of the brand, making the client that can both appreciate and afford them just as rare as the watches themselves.

However, the versatility, ergonomics, and style of the Convexe series have been a considerable driving force in drawing attention to their craft. The Convexe case is smartly constructed such that it perfectly meets the curve of the wrist while the curvature of the bezel and crystal provide an expansive view of the dial – which is virtually indistinguishable from the movement. The brand recently took another stride and downsized two of its bestselling watches, the Balancier Convexe S2 and the Double Balancier Convexe. Now at Geneva Watch Days, these models have been introduced in carbon composite, the brand’s first carbon case.

Balancier Convexe S2 41.5mm in Carbon

The Balancier Convexe S2 showcasing the brand’s signature inclined balance wheel is a watch that perfectly illustrates the unique way in which Greubel Forsey’s pursuits of chronometry, three-dimensional construction and craft are integrated as one, where each elevates the other to the level of art.

In the new carbon edition, the curved case, main plate and main bridge are executed in carbon. Cabon composite cases are constructed by layering multiple sheets of carbon fiber, which are impregnated with resin. The layers are stacked in a mold and shaped under heat and pressure, and then cured. However, the unique curvature of the case, according to Greubel Forsey, demanded the use of 16 tonnes of pressure per square centimeter, which is eight times higher than what is typically employed for traditionally shaped carbon or steel cases. The brand’s approach of multiplying the number of layers and using extremely thin layers in the micrometer range (1 to 5 microns per layer) achieves a more tightly packed and precisely shaped carbon case, which contributes to the overall durability. The fibres are also orientated to match the curvature of the Convexe case.

The case nevertheless maintains its alternating finishes, where the matte upper surfaces of the bezel and lugs create are contrasted by the brushed textures adorning the chamfer of the bezel and the case band. The crown has also been engraved in relief with the GF initials.

The carbon case and mainplate accomplish more than just reducing the watch’s weight; they make the watch appear smaller, more compact. The carbon mainplate also gives somewhat of an impression that the components in the movement are mysteriously suspended within the case. But most of all, the carbon mainplate’s juxtaposition with the exquisitely polished steel and titanium components provides a contrast that exists nowhere else.

The main bridge that forms the dial features a power reserve indicator at two o’clock while a pair of stacked, co-axial mainspring barrels sit under a relief-engraved barrel cover at 10 o’clock. The barrels rotate twice as fast as a regular barrel, making one revolution in 3.2 hours to minimize the chances of the coils of the mainspring sticking together. Notably, the second barrel has a slipping bridle that relieves excess pressure from overwinding.

The motion works as well as part of the keyless works are supported by an openworked titanium bridge that rises from the dial to meet them on an elevated plane. The plate terminates in a line that spans from nine to five o’clock, where it intersects with a plate that slopes downwards at a 30-degree angle, showcasing the brand’s inclined balance wheel and escapement suspended by an openworked, architectural cock. The purpose of mounting the balance at a 30-degree tilt from the vertical plane is to limit errors in rate caused by gravity in both the horizontal and vertical positions.

Previously downsized from 43.5mm, the case has a base diameter of just 41.5mm and measures 44mm across its bezel with a height of 12.85mm excluding crystal. Two versions are available, differing only by the colour of the sub-dial: blue or black. They are limited to 22 pieces each.

Double Balancier Convexe 42.5mm in Carbon

The Double Balancier stands as Greubel Forsey’s most intriguing and mechanically exotic model. While watches of this format have become slightly more common today, the Double Balancier still differs in two ways. First, the two balance wheels are inclined at an angle with respect to gravity as well as to each other, so that the positional errors experienced by one balance in any given position are compensated by those in the other via the differential. Driven by the center wheel of the movement, the differential has a lateral construction made up of three co-axial wheels in which the top and bottom wheels drive the pinion of the fourth wheels on its right and left.

Secondly, the differential also doubles as a remontoire d’egalité. Visible on both the front and back of the watch is a pair of spiral springs attached to the spokes of the top and bottom wheels. This set of springs is rewound every four minutes by the mainsprings and delivers energy to the balance wheel in short, controlled bursts, ensuring that the balance wheel’s amplitude remains unaffected by torque fluctuations as the mainspring winds down. The middle wheel in the differential then transmits the equalized force to the center wheel, which carries the hands as well as drives the seconds indicator via an auxiliary train.

The new Double Balancier Convexe measures 42.5mm at its base, 44.4mm across its bezel and has a height of 13.75mm, excluding crystal. It is available in two carbon versions, each limited to 22 pieces. In contrast to the Balancier Convexe S2, both versions have their mainplates and bridges made in titanium – one has a bluish green coating while the other is black. Both are incredibly striking, offering a contrast that is worth savoring in person.

Tech Specs

Balancier Convexe S2 41.5mm in Carbon

Movement: Manual winding; 3Hz or 21,600 vph; 72-hour power reserve on two serially coupled barrels
Functions: Hours, minutes, small seconds; power reserve indicator
Case: 41.5mm by 12.85mm (excluding crystal); carbon; water-resistance to 50m
Dial: Polished, with engraved and lacquered minute-circle with polished hour indexes filled with Super-Luminova; polished steel hands filled with Super-Luminova; gold small seconds dial
Strap: Rubber with texture in relief; titanium and carbon folding clasp, engraved GF logo
Availability: Two versions (with either black or blue sub-seconds dial), each limited to 22 pieces

Double Balancier Convexe 42.5mm in Carbon

Movement: Manual winding; 3Hz or 21,600 vph; 72-hour power reserve on two serially coupled barrels
Functions: Hours, minutes, small seconds; power reserve indicator; 4-minute display for the spherical constant differential
Case: 42.5mm by 13.75mm (excluding crystal); carbon; water-resistance to 50m
Dial: Polished, with engraved and lacquered minute-circle with polished hour indexes filled with Super-Luminova; polished steel hands filled with Super-Luminova; small seconds and differential dials in gold
Strap: Rubber with texture in relief; titanium and carbon folding clasp, engraved GF logo
Availability: Two versions (with either black or green dial), each limited to 22 pieces