Greubel Forsey Double Balancier Convexe Carbon
Movement
Manual winding
Size
42.50 mm

Overview

Two balances, one average

The Greubel Forsey Double Balancier Convexe, Carbon execution, in carbon and titanium, 42.5 mm and 14.35 mm overall (13.75 mm case), water-resistant to 50 m. Two balance wheels averaged by a spherical differential over 4 minutes, with hours, minutes, small seconds and power reserve; manually wound; a limited edition of unpublished size.

The Double Balancier Convexe carries two balance wheels linked by a spherical differential, which is the mechanism the model is named for. The brand's framing is a watch that goes under a fitted sleeve or sits open on a bare wrist, and lets the owner show or cover the movement as they like.

The differential sits between 6 and 7 o'clock, visible on the dial. Two balances never run at exactly the same rate; the differential takes both and passes their average to the hands, resolving it in four-minute sequences, so that the error of one wheel is set against the other rather than passed on. The plate is titanium, grained, which the brand notes as a hard finish on a hard metal, and each balance bridge is openworked, flat black-polished and hand-bevelled. The lettering on the barrel cover is drawn to suggest its rotation. Manual winding, 72 hours of reserve.

For collectors

The differential is placed on the dial side, between 6 and 7 o'clock, so its four-minute cycle can be watched rather than inferred.

Key details

Case materialCarbon and titanium
MovementManual winding
LimitationLimited edition

Design and engineering

  • Spherical differentialLinks the two balances and passes their average rate to the train, resolving it over 4-minute sequences. Set between 6 and 7 o'clock, on view.
  • Grained titanium plateThe main plate is titanium, hand-grained; titanium is hard, so the brand counts the finish among its more demanding ones.
  • Openworked balance bridgesEach bridge is openworked, flat black-polished and bevelled by hand — a combination the brand singles out for the skill it takes on a pierced part.
  • Convexe case42.5 mm across and 14.35 mm overall; the bridges and main plates are titanium.
  • BarrelThe lettering on the barrel cover is drawn into the case's lines to suggest the barrel's rotation; 72 hours of guaranteed reserve.

Movement

  • Manual winding; Double Balancier; hours, minutes, small seconds, power reserve
  • Spherical constant differential, one rotation in 4 minutes
  • Titanium plate, grained; openworked flat black-polished balance bridges
  • 21,600 vibrations per hour
  • Power reserve 72 hours

The reference

Technical specifications

Double Balancier Convexe Carbon
CollectionBalancier
MovementManual winding
FunctionsMovement with manual winding, Double Balancier, hours and minutes, small seconds, spherical constant differential rotation in 4 minutes, power reserve
Case dimensions42.50 mm
Case thickness13.75 mm (14.35 mm including sapphire crystals)
Case materialCarbon and titanium
Water resistance5 atm - 50 m - 164 ft
Power reserve72 hours
Frequency21,600 vibrations/hour
LimitationLimited edition
ReferenceNot published by the brand — sourced by model and execution

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Double Balancier Convexe Carbon · Ref. Balancier

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