
- 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differential over 4 minutes, with hours, minutes, small seconds and power reserve; manually wound; a limited edition of unpublished size.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
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
| Collection | Balancier |
|---|---|
| Movement | Manual winding |
| Functions | Movement with manual winding, Double Balancier, hours and minutes, small seconds, spherical constant differential rotation in 4 minutes, power reserve |
| Case dimensions | 42.50 mm |
| Case thickness | 13.75 mm (14.35 mm including sapphire crystals) |
| Case material | Carbon and titanium |
| Water resistance | 5 atm - 50 m - 164 ft |
| Power reserve | 72 hours |
| Frequency | 21,600 vibrations/hour |
| Limitation | Limited edition |
| Reference | Not published by the brand — sourced by model and execution |
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