Greubel Forsey Double Balancier Convexe: eleven pieces

Stephen Forsey and Robert Greubel built their Geneva workshop on a single conviction: a watch reveals its maker through what cannot be hidden. The Double Balancier Convexe, limited to eleven pieces, makes this philosophy visible. Two inclined balance wheels operate together through a spherical differential mechanism, all exposed through an open dial in black ceramic and 5N red gold. There is no ornament here, no applied decoration to obscure the decision. The ceramic case resists distraction as much as scratching; the red gold bezel and caseback offer warm counterpoint. The movement entire lies open to inspection.

Each balance wheel is angled to work in concert with its partner, connected through the spherical differential to calculate and compensate for the variations that accumulate across any mechanical watch. Two inclined oscillators, polished and brushed surfaces on the differential itself, hand-applied hour markers in white gold. The dial is transparent because Greubel Forsey judges a watch by what occurs beneath it, not by the story attached to it. Forsey and Greubel, both trained at the Bienne School of Watchmaking, oversee production themselves in their independent Geneva manufacture. The approach tolerates no volume; each Double Balancier Convexe emerges from weeks of hand finishing and assembly that cannot be rushed or automated.

The spherical differential sits at the centre of the concept: two independent balance wheels compensating for each other’s irregularities in rate and amplitude. The convex arrangement, visible through the open dial, creates an optical effect that mirrors the mechanism’s internal geometry. Polished finishes on the differential’s surfaces demand hand work throughout; brushed surfaces follow a pattern that emphasises function rather than decoration. The caseback offers a second view of the movement’s lower plate and balance wheel assembly, a choice that serves Greubel Forsey’s conviction that transparency regarding what a watch actually achieves matters more than mystery or claim.

Black ceramic for the case, chosen for its resistance to wear and its visual neutrality as a background. The 5N red gold used for bezel and caseback meets 75 per cent purity, a distinction that ensures colour consistency across the entire run of eleven pieces. Each timepiece carries a unique serial number and a certificate detailing the specific rates and performance characteristics of its individual balance wheels. The documentation reflects a practice uncommon in watchmaking: collectors receive detailed evidence of what their watch actually delivers, not marketing language about what it promises.

The spherical differential itself required seven years of development before Greubel Forsey felt confident releasing it to collectors. This mechanism, which sits at the heart of the Double Balancier concept, allows two independent balance wheels to operate in concert, each compensating for the other’s irregularities in rate and amplitude. The convex arrangement of the balance wheels, visible through the open dial, creates an optical effect that mirrors the internal geometry of the movement. The polished finish applied to the differential’s surfaces demands hand work that cannot be rushed or automated, adding weeks to the assembly of each piece.

Black ceramic was chosen for the case not for its contemporary appeal but for its resistance to scratching and its absolute neutrality as a visual background. The material requires specialised tooling and firing processes that few watchmakers undertake; Greubel Forsey sources its ceramic from Swiss suppliers who work exclusively with high-end manufactures. The 5N red gold used for the bezel and caseback meets the 75 per cent purity standard, a designation that distinguishes it from standard 18-carat gold and ensures colour consistency across the entire production run of eleven pieces.

The open dial construction exposes movements that would normally remain concealed, a choice that demands perfection in finishing throughout. Greubel Forsey applies both polished and brushed surfaces to the spherical differential according to a pattern that emphasises the mechanism’s geometry rather than decorative intent. Hand-applied hour markers and hand-finished hands in white gold complete the dial, while the caseback allows a second view of the movement’s lower plate and balance wheel assembly. The transparency of design serves the manufacture’s conviction that beauty emerges from function executed to the highest standard.

The eleven pieces are produced across a single calendar year, with each watch carrying a unique serial number and accompanied by a certificate of authenticity detailing the specific rates and performance characteristics of its balance wheels. Collectors receive detailed documentation of their individual timepiece’s chronometric performance, a practice uncommon in watchmaking and reflective of Greubel Forsey’s transparency regarding what a watch actually achieves. Pricing for the Double Balancier Convexe begins at approximately 550,000 Swiss francs, with regional availability confirmed through Seddiqi’s boutiques and website in the UAE.

Imagery courtesy of Greubel Forsey (@seddiqi_uae).