Hands on with the Montblanc ExoTourbillon Chronographe
In 2010 Montblanc launched the ExoTourbillon and at this year’s SIHH Montblanc treated us on two new version, in 18 carat white and red gold. The ExoTourbillon is Montblanc’s first combination of a chronograph (not just a chronograph) and a tourbillon (not just a tourbillon).
All classic watchmaking expertise of Montblanc’s Villeret manufacture, the former Minerva manufacture, is brought together in this peerless timepiece. A single pusher chronograph – Minerva is famous for its magnificent chronograph calibers – and a tourbillon that is singularly distinctive, brilliantly finished and innovative.
The ExoTourbillon combines a tourbillon and chronograph with a two-time-zone display, day/night indicator on regulator-style display. The Montblanc Villeret manufacture is one of the few holdouts using in-house manufactured balance springs, while the majority of Swiss watchmaking firms use the famous Nivarox-supplied balance springs. In fact, all Montblanc Collection Villeret timepieces are equipped with an entire in-house built escapement, from the balance wheel and escape wheel to the balance spring with Phillips terminal curve and lateral lever.
In the ExoTourbillon Chronographe, you can see the tourbillon at 12 o’clock. Upon closer inspection you can see that it is a most unusual tourbillon.
In a typical tourbillon, the escapement and all its parts are housed within a cage that spins on its own axis. In the ExoTourbillon the massive 14.5 mm balance wheel is actually outside the rotating cage! Montblanc says this has been done to isolate the movements that perturbed the escapement. The result is a tourbillon cage that is smaller than the balance wheel, and which oscillates outside the cage system. That’s the reason for the ‘Exo’ preposition.
The photo shows that the balance wheel sits higher then the balance spring. Without the large, and relatively heavy balance wheel, the tourbillon cage has a smaller mass and therefore needs less energy to drive its rotation. Montblanc report a gain in energy of approximately 30 percent thanks to the (patented) ExoTourbillon system. The tourbillon cage performs a four-minute rotation.
While the upper part of the dial gives the stage to the tourbillon, the lower part of the dial shows all indicators for the time, second timezone, day/night and chronograph.
At the 9 o’clock position is the small seconds hand in its own sub dial, that has the same grey color as the dial. At the center bottom, is a double hour indicator with two separate hour hands that each can indicate the time in a different timezone. Local time is indicated by the hour hand with the white tip and the blued steel hour hand indicates the home time. Between the 4 and 5 o’clock position is the day/night indicator with 24-hour display, which is connected to the home time (blued steel hour hand).
When the watch is worn in the home timezone, the two hour hands are always positioned one atop the other. When the wearer travels to a different time zone, pushing the button at the 8 o’clock position will advance the local-time hour-hand (with white tip) in single-hour increments until the hand indicates the correct local time.
Centrally is the minute hand – regulator style – and the chronograph seconds counter. Towards the 3 o’clock position is the 30-minute totalizer, which uses a single hand to keep track of the elapsed minutes in two 15-minute segments.
The movement of the ExoTourbillon is caliber MB M 16-60, a mono pusher or mono-poussoir in French, chronograph with the start, stop and reset functions directed from a single pusher positioned in the crown. It is a typical Minerva chronograph caliber with a classical column wheel and horizontal clutch. It goes without saying that every part, visible for the owner or not, is hand finished to the highest degree.
The case 18 carat white or red gold case measures 47 mm in diameter and 16,67 mm in height. In the front is a domed sapphire crystal, while the case back has a transparent pane of sapphire crystal inset, beneath hinged cover! Typical for the Montblanc Villeret 1858 Collection are the lugs with a leather cover that hides the small opening between strap and case. By the way, both versions are limited to just 8 pieces!
Conclusion: All-together a most impressive timepiece that houses one of the finest chronograph calibers, offers perfect chronometrical rates due to the patented ExoTourbillon and has a very handy double timezone function. Montblanc’s ExoTourbillon delivers the best of several worlds.
You can find more information on the Montblanc website here.
This article is written by Frank Geelen, executive editor for Monochrome Watches.