Greubel Forsey Double Balancier Convexe: what does its owner think?

The Greubel Forsey Double Balancier Convexe, launched in 2022, combines one of Greubel Forsey’s most characteristic chronometric research projects with its Convexe case architecture designed to follow the natural curvature of the wrist more closely. Its mechanical principle uses two independent balance wheels, each inclined at 30 degrees in a different plane and linked by a constant spherical differential that establishes an average of their respective rates. Unlike a double tourbillon, the two regulating organs do not rotate inside cages: they remain fixed within their inclined planes while geometry and the differential perform the intended averaging function. The manually wound movement provides 72 hours of power reserve and exposes much of its 371 components on the dial side.

The first generation uses a 43.5 mm titanium case before Greubel Forsey redesigns the watch around a smaller 42.5 mm diameter in 2023. Carbon variations subsequently expand the collection while production remains extremely limited.

Design & legibility: two balance wheels at the centre of a three-dimensional architecture

The Double Balancier Convexe has almost no conventional dial in the usual sense. The movement directly forms the landscape within which the hours, minutes, small seconds and power reserve are displayed. The two balance wheels occupy the lower and central sections, each positioned on its own inclined plane and supported by an extensively openworked bridge. Above them, a large barrel bridge and different plates organise the hour display. The two inclined balance wheels positioned side by side form the fundamental distinguishing feature of the Double Balancier Convexe. Their arrangement creates unusual depth: depending on wrist angle, certain components appear almost to rise from the dial while others disappear beneath bridges or behind the hour ring. The watch is therefore discovered more as mechanical architecture than as a flat time display.

Hours and minutes remain comparatively straightforward despite this construction. Large hands are curved to follow the geometry of the crystal and movement periphery, while the minute track develops across a three-dimensional ring whose shape varies between generations. The tips of the hands receive luminous material to improve reading in reduced light. The curvature of the hands brings their tips closer to the graduations despite the considerable depth of the movement. The solution is as aesthetic as it is functional: a completely flat hand would appear visually disconnected from the peripheral ring positioned on another level. Small seconds and power reserve each occupy their own zones without attempting perfect symmetry, an appropriate choice for a watch prioritising spatial organisation rather than conventional dial design.

The constant spherical differential visible between the two balances creates a third mechanical spectacle. It completes one full rotation every four minutes and links the oscillators in order to transmit their averaged rate to the gear train. It is therefore not merely decoration positioned between two balance wheels but an essential part of the invention itself. The spherical differential transforms the performance of two distinct regulating organs into one averaged rate transmitted to the time display. Its constant motion provides an animation slower than that of the balances, allowing several mechanical rhythms to be observed simultaneously. The balances oscillate rapidly at 3 Hz while the differential turns slowly, creating a display in which technical functions can be understood visually.

Finishing plays a decisive role in maintaining this mechanical legibility. Openworked balance bridges receive flat black polishing and hand-polished bevels, plates use frosted or circular-grained surfaces, gold chatons surround the jewels and several inscriptions are executed in relief. On the 42.5 mm titanium version, the titanium mainplate itself is frosted, a particularly demanding finish on this hard material. Decoration is not added after the fact but used to visually separate the levels and functions of the movement. A black-polished bridge reacts to light differently from a frosted plate, while a bright bevel clearly separates two adjacent planes. This multiplication of textures is particularly important on a watch almost entirely without a conventional dial.

Convexe case, strap and comfort: curvature as a solution to substantial dimensions

The Convexe case is designed to curve both on the dial side and the caseback. Seen from above, the watch retains a generally circular appearance, but its profile drops towards the strap ends in order to follow the natural shape of the wrist. The lugs are integrated into this architecture and the sapphire crystals themselves are curved. Convexe construction attempts to distribute a large watch around the wrist rather than simply place a thick cylinder on top of it. This principle is particularly useful on the original 43.5 mm Double Balancier Convexe, whose dimensions remain substantial despite the use of titanium. Geometry does not make the watch small, but it reduces the impression of a rigid, vertically stacked case.

The first generation presented in 2022 measures 43.5 mm in diameter and approximately 14.35 mm high when the curved crystals are included. Titanium is the principal case material, selected for its low mass and to enable a more sporting use than previous Double Balancier watches principally produced in precious metals. The case is rated to 10 ATM, or 100 metres. One hundred metres of water resistance represents an important break from previous Double Balancier watches limited to 30 metres. It theoretically allows far freer everyday use provided water resistance is correctly maintained. This development directly contributes to the Convexe positioning, which attempts to make Greubel Forsey constructions better suited to active wear.

In 2023, Greubel Forsey reduces the caseband diameter to 42.5 mm. The bezel nevertheless measures approximately 44.4 mm at its broadest point and overall height remains around 14.35 mm. The transformation is not a simple proportional reduction: the convex profile, angles, movement positioning and several finishing details are reworked. The 42.5 mm generation should be considered a genuine ergonomic redesign rather than a miniature version of the 2022 watch. One millimetre appears modest on a specification sheet but significantly changes the relationship between the 37.7 mm movement and the case. The mechanics occupy a greater percentage of the available space and the watch loses some of the peripheral volume of the first model.

The watch can be fitted to a textured rubber strap or, in certain configurations, an integrated titanium bracelet. Rubber strengthens the contemporary character and further reduces mass, while the metal bracelet creates a more sculptural appearance and visually continues the surfaces of the case. The rubber strap is the most coherent configuration when comfort and low weight matter more than the spectacular effect of the titanium bracelet. Attachments are specific to the Convexe architecture, naturally limiting the use of generic alternatives. The folding clasp follows the finishing of the case and should be adjusted accurately because a watch of this size becomes significantly less comfortable if allowed to move freely around the wrist.

Double Balancier: two 30° oscillators and a constant spherical differential

The mechanical principle of the watch comes from research considerably older than the Convexe collection. Greubel Forsey initially explores a double inclined-balance system within its Experimental Watch Technology programme, first using two superimposed regulating organs inclined at 20 degrees. A 35-degree evolution follows in 2013 before the present architecture is introduced in 2016 with two distinct balances inclined at 30 degrees. The objective is to reduce the influence of the least favourable positions of a regulating organ under gravity. The two inclined balances are intended to prevent both oscillators from simultaneously occupying a perfectly horizontal or vertical position. They operate in different three-dimensional planes, meaning their positional errors do not necessarily manifest in the same way at the same moment.

The two oscillators do not transmit their rates independently to the hands. They are united by a constant spherical differential, a mechanism completing one rotation in four minutes and establishing an average of their behaviour. This average is then transmitted to the remainder of the gear train. The differential allows the movement to exploit two chronometric behaviours simultaneously rather than arbitrarily favour one balance wheel. The concept differs from a tourbillon: instead of rotating an escapement in order to distribute its positional errors, Greubel Forsey uses two fixed but inclined regulators and mechanically averages their rates. This explains why the model belongs to the Balancier collection rather than to the Manufacture’s Tourbillon families.

The movement of the 42.5 mm generation measures approximately 37.7 mm in diameter and 9.46 mm thick. It contains 371 components and 50 jewels, several mounted in gold chatons. The variable-inertia balances measure approximately 10 mm and use gold mean-time screws. Their frequency is 21,600 vibrations per hour, or 3 Hz. The relatively moderate 3 Hz frequency favours large, high-inertia balance wheels rather than simply increasing operating frequency. The hairsprings use Phillips terminal curves and Geneva-style studs. The complete arrangement gives unusually direct visual access to a regulating architecture that would normally be largely hidden beneath a dial and more conventional bridges.

Energy comes from two coaxial barrels coupled in series. They rotate relatively quickly, completing one turn in approximately 3.2 hours, and one uses a slipping spring to prevent excessive tension. Guaranteed chronometric power reserve reaches 72 hours. The two series-coupled barrels provide three days of autonomy while supplying two regulating organs and their differential. Winding is exclusively manual, a choice consistent with the visible movement architecture and with the desire not to conceal the back beneath an oscillating weight. A sector power-reserve indication allows available energy to be monitored directly, particularly useful on a watch whose owner is likely to alternate it with several other pieces.

Chronological milestones and main models (2013–2025)

(2013) Greubel Forsey Double Balancier 35° Second Experimental Stage:

The Greubel Forsey Double Balancier 35° represents an essential stage between the earliest Experimental Watch Technology prototypes and the present system. It uses two oscillators positioned in different three-dimensional planes and each inclined at 35 degrees, linked by a spherical differential that establishes their averaged rate. Its 43.5 mm white-gold case measures 14.34 mm thick. The movement contains 365 components, operates at 21,600 vibrations per hour and provides 72 hours of reserve. Water resistance is limited to 30 metres. The display includes hours, minutes, small seconds and power reserve. Only six examples are produced. The 35-degree inclination notably enables the use of large-diameter balance wheels, but Greubel Forsey continues its research before arriving at the 30-degree arrangement that becomes the basis of the modern Double Balancier.

(2016) Greubel Forsey Double Balancier Definitive 30° Architecture:

The Greubel Forsey Double Balancier introduces the mature form of the invention subsequently used by the Double Balancier Convexe. The two balance wheels are now separated and each inclined at 30 degrees in distinct planes. They are linked by a constant spherical differential rotating in four minutes and transmitting their averaged rate. The case measures 43 mm in diameter and 13.38 mm thick and is offered principally in white gold, red gold and selected sapphire executions. The movement contains 285 components, operates at 21,600 vibrations per hour and provides 72 hours of power reserve. Water resistance remains 30 metres. Greubel Forsey produces a total of 55 pieces between 2016 and 2022. This generation permanently establishes the chronometric architecture subsequently made more sporting by the Convexe collection.

(2019) Greubel Forsey GMT Sport First Sporting Convexe Architecture:

The Greubel Forsey GMT Sport does not use the Double Balancier but plays an important role in the development of the future Double Balancier Convexe. It introduces the sporting case direction that gradually becomes the Convexe identity: a case appearing circular from above but strongly curved in profile to follow the wrist. Lugs integrate directly into this shape and the strap continues the case lines. Titanium and greater water resistance than many historical creations support less formal use. This construction demonstrates that a highly complex Greubel Forsey mechanism can be installed within a case conceived from the outset around ergonomics. The concept subsequently provides a foundation for the Balancier S and then the dedicated Convexe collection before receiving the Double Balancier in 2022.

(2022) Greubel Forsey Double Balancier Convexe Titanium 43.5 mm:

The Greubel Forsey Double Balancier Convexe combines the Double Balancier invention and Convexe architecture for the first time. Its titanium case measures approximately 43.5 mm in diameter and 14.35 mm including the curved crystals. It is water-resistant to 100 metres, a considerable improvement over the 30 metres of the previous Double Balancier. Its manually wound movement exposes two balances inclined at 30 degrees, the four-minute spherical differential, small seconds and power reserve. Autonomy reaches 72 hours and frequency 21,600 vibrations per hour. The watch can be fitted with either rubber or an integrated titanium bracelet. Total production is limited to 66 pieces, at 22 watches per year between 2022 and 2024. This first generation retains substantial physical presence but radically changes how the Double Balancier can be worn.

(2022) Greubel Forsey Double Balancier Convexe SHH Purple Edition:

The Greubel Forsey Double Balancier Convexe SHH Edition is created for Sincere Fine Watches to mark the opening of its SHH boutique in Singapore. It retains the large titanium Convexe case and mechanics of the 2022 generation but uses a specific purple colour treatment that significantly changes the perception of the different movement levels. The two balance wheels remain inclined at 30 degrees and linked through the constant spherical differential, while the hand-wound movement retains 72 hours of reserve. The case continues to follow the wrist through its strongly curved profile. Only six examples are produced, making this one of the rarest interpretations of the first Double Balancier Convexe. It also demonstrates how dramatically colour can transform an architecture in which a large part of the movement is visible directly from the dial side.

(2023) Greubel Forsey Double Balancier Convexe Titanium 42.5 mm:

The Greubel Forsey Double Balancier Convexe is comprehensively redesigned around a 42.5 mm caseband and a bezel whose maximum width reaches approximately 44.4 mm. Overall height including both crystals remains around 14.35 mm. Its natural titanium case combines polished and satin-finished surfaces while the titanium mainplate is frosted. The hand-wound movement measures 37.7 mm, contains 371 components and 50 jewels and retains the two 30-degree balances, four-minute spherical differential and 72-hour reserve. Frequency is 21,600 vibrations per hour. Water resistance reaches 100 metres and the watch can receive either a grey rubber strap or integrated titanium bracelet. This edition is limited to 88 examples produced between 2023 and 2026.

(2023) Greubel Forsey Double Balancier Convexe Carbon Green First Carbon Greubel Forsey:

The Greubel Forsey Double Balancier Convexe Carbon Green transfers the new 42.5 mm architecture into a material never previously used for a Greubel Forsey case. Carbon and titanium construction combines with a curved sapphire crystal, a glazed caseback and a carbon crown. The arrangement of the fibres makes every case visually individual. The green version combines different green and blue shades across the principal bridge, mainplate and hour ring. The hand-wound movement retains 371 components, 50 jewels, a 3 Hz frequency and 72 hours of reserve. Its 10 mm balance wheels remain inclined at 30 degrees and linked through the constant spherical differential. Water resistance is rated here to 50 metres. Only 22 watches are produced in this colour, accompanied by a matching textured strap.

(2023) Greubel Forsey Double Balancier Convexe Carbon Black Monochromatic Execution:

The Greubel Forsey Double Balancier Convexe Carbon Black uses the same 42.5 mm carbon-and-titanium construction but adopts a much more homogeneous black presentation. This treatment strongly emphasises polished movement details: black-polished balance bridges, bright bevels, screws and chatons stand out particularly clearly against the dark environment. The movement still contains 371 components and 50 jewels, with two coaxial barrels coupled in series and 72 hours of reserve. The 30-degree inclined balances operate at 21,600 vibrations per hour and remain linked through the four-minute spherical differential. Water resistance reaches 50 metres. The strap is made from a textured non-animal material and closes through a titanium-and-carbon folding clasp. This variation is also limited to 22 pieces.

Choosing the right version: first generation, 42.5 mm or carbon

The 2022 43.5 mm version carries the greatest historical significance because it represents the first combination of the Double Balancier and Convexe case. Its total production of 66 pieces and launch status may therefore be particularly attractive to a collector. Its dimensions are nevertheless substantial. The first generation principally suits someone seeking the founding configuration and accepting a highly assertive wrist presence. Titanium limits the mass but does not alter the physical space occupied by the watch.

The 42.5 mm titanium version represents a more rational choice for someone intending to wear the watch frequently. A one-millimetre difference looks modest on paper but accompanies changes to the profile, proportions and integration of the movement. It also retains 100 metres of water resistance. The 42.5 mm titanium model is the most versatile Double Balancier Convexe configuration. Rubber prioritises comfort and lightness while the titanium bracelet creates a more spectacular and visually unified presence.

Carbon versions are visually and physically lighter but water resistance decreases to 50 metres. Their surface cannot be restored or polished in the same manner as a conventional metal case, making the condition of the material especially important on a pre-owned example. Carbon should be selected as much for its individual texture and character as for its reduced mass. The black version particularly highlights movement finishing while green creates a substantially stronger chromatic presence.

Manual winding forms an important part of the ownership experience. The 72-hour reserve means that the crown does not need to be used every day, while the indicator makes remaining autonomy easy to monitor. Winding action should remain regular and the slipping-spring arrangement protects against excessive tension. The winding ritual is especially coherent on a watch whose mechanics form the principal visual spectacle. Someone seeking a completely automatic watch requiring almost no regular interaction will naturally need to accept a different philosophy.

Finally, inspection of a pre-owned example should extend well beyond the condition of the case. Polished bridges, inward angles, chatons, screws, frosted surfaces and curved sapphire crystals are all components whose finish could be altered by inappropriate intervention. Both balance wheels should oscillate regularly and the differential should operate without visible irregularity. A documented Greubel Forsey service history becomes especially important with a highly specialised 371-component movement. Other customers’ opinions are essential.

Conclusion

The Greubel Forsey Double Balancier Convexe is aimed at collectors seeking an extremely sophisticated approach to chronometry without relying on a tourbillon. Its two balance wheels inclined at 30 degrees and constant spherical differential transform fundamental research into regulator positioning into mechanical architecture visible directly from the dial side. The original 43.5 mm version carries the historical importance of the launch, the 42.5 mm generation significantly improves ergonomics and carbon editions add lightness and individuality. Across every configuration, the 72-hour reserve, manual winding and exceptional level of hand finishing remain central to the experience. The final choice therefore depends primarily on material, diameter, desired water resistance and preference between rubber and titanium bracelets.

To learn more about Swiss watch brands, check out the ranking of the most popular Swiss watch brands.

To compare comfort, accuracy, winding experience and the long-term behaviour of such a complex timepiece with real ownership, Dialicious customer reviews provide a particularly useful complement.

(Updated September 2026)