— Two Greubel Forsey timepieces have been pre-selected for the Grand Prix d’Horlogerie de Genève and will take part in the final competiton.
Greubel Forsey launched the first GTM Asymétrique in 2011, featuring a white gold case. The model that is taking part in the Grand Prix de l’Horlogerie 2013 is the latest version, in red gold 5N. Apart from the material of the case and the plates and bridge that have undergone a galvanic treatment and now boast an anthracite colour, the 2013 and 2011 versions are similar. The movement is the same.
The main characteristic of the GMT Asymétrique is the three-dimensional temporal representation: a rotating terrestrial globe offering a truly original view of time all over the world. This technical yet poetic marvel provides us with a completely new way of perceiving the different time zones. While the globe makes one complete rotation every 24 hours anticlockwise – the Earth’s natural rotational direction – the position of the continents can be neatly cross-referenced with the 24-hour, day-and-night indicator on the equatorial chapter ring. The globe is complemented at 10 o’clock by the 12-hour second time zone dial giving a precise indication of the time in a designated second country or city. Turning over the GMT reveals the beautifully crafted ‘worldtime’ disc bearing the names of 24 cities each representing one of the different global time zones.
Cascading clockwise around the dial-side are the main indications comprising a principal hour-minute dial at 1 o’clock, on top of which is a small seconds dial at 2 o’clock, while at 3 o’clock is a sectorial power reserve indicator. The specially developed movement of the GMT features the 25° inclined Tourbillon 24 Secondes cage, one of Greubel Forsey’s major patented inventions.
Double Balancier 35°
The Double Balancier 35° features two inclined fixed‐oscillators. This unique regulating system comprises two inclined oscillators and escapements. They are driven through a spherical differential, which provides the average of their rates via the gear train to the time display. The two inclined oscillators are not superimposed, but are spatially disposed in different three dimensional planes.
The skeletonised gold hands with high‐legibility Super‐LumiNova tips indicate the time against a polished black‐oxidised gold chapter ring. Between the two visible inclined balances of the Double Balancier 35°, the small seconds at 7 o’clock displays the running instantaneous average of the two regulators, while a 72‐hour power reserve indicator at 2 o’clock keeps track of the optimal power available from the two co‐axial, fast‐rotating mainspring barrels. The 35° inclination of the inclined balances allows for larger diameter balance wheels (better inertia for more stable timekeeping) in a very comfortably‐sized 43.5mm case.
The complete manual winding movement comprises 365 components, 28 of which make up the spherical differential. It is powered by two concentric fast‐rotating mainspring barrels that provide optimal power for 72 hours. The two oscillators feature variable inertia balance wheels, Phillips terminal curves and beat at 3Hz/21,600 APH. Plates and bridges are in nickel silver, frosted and spotted, with polished bevelling and countersinks, straight‐grained flanks and anthracite treatment (NAC).