In the last 10 years, the tourbillon has become a prevalent complication with every manufacture from the small, like Frederique Constant, to the conglomerate owned, like Jaeger-LeCoultre, putting out their fabulous rendition, each one trying to outdo the other in complexity or just prove they have the capabilities to produce one at all.
More than just a proliferation of the cagey mechanism, what perturbed me is that until recently there was no real proof that the tourbillon improved timing. It was originally developed by Abraham Louis Breguet to mitigate the effects of gravity on the escapement in a pocket watch, which was usually in a vertical position in the gentleman’s fob pocket. With the advent of the wristwatch, the same construction and logic applied despite completely different positions and dynamics.
There was no real evidence that the same principles of physics were at work in a watch. In fact, when fellow watch geeks field-tested watches with tourbillons against those with regular escapement constructions (even in inexpensive watches), those without the tourbillons seemed to win the wars of timing. Plus, the tourbillon adds a huge cost to any watch and it may be unnecessary, particularly because of the claims of improved timing by certain brands. Granted some tourbillons deliver, such as Jaeger LeCoultre, which won the International Timing Competition – Concours International de Chronométrie– in 2009 with the Master Tourbillon with an impressive 914 out of 1000 points. JLC also took second place with their double axis Gyrotourbillon, only one point behind.
Another niggling point: It used to be that very few manufactures had the capabilities and talent to build a tourbillon. Relatively few watchmakers even possessed the know-how to put the things together properly. With the advent of the CNC machine, building a tourbillon got a lot easier. That’s not to say anybody can punch in a code into the CNC machine and voila! you’ve got a working tourbillon. However, even fashion house Chanel has a tourbillon in their watch line up. Yeah, like I said, everybody has one.
And yet, there’s no denying that the complication holds fascination for the public or the brands wouldn’t continue to make them. The truth is timing isn’t the primary reason for purchase but the wonder of the tourbillon itself. There’s no denying its intricate movements are perhaps the most interesting to watch of all the gears and wheels. Still, it’s a high premium to pay for a complication that doesn’t necessarily perform as advertised and is just a conceit, albeit one of considerable beauty.
Enter Robert Greubel and Stephen Forsey. They felt the tourbillon was one of the complications that hadn’t been explored thoroughly in the wristwatch. Establishing their company Greubel Forsey in 2004 with the express mission to improve the tourbillon and make it a relevant complication for the wristwatch, they introduced their first invention in 2004. The ‘Double Tourbillon 30°’ features two tourbillons, one rotating inside the other.
What Robert and Stephen first determined is that inclining the balance offers performance advantages, especially when combined with a tourbillon cage. Here’s the basic principle: consider that when a balance wheel is flat, most of the weight is on the bottom pinion/axel (less friction so the watch runs faster, while in the vertical position, it’s supported by both pinions (more friction, so watch runs slower. The greatest difference in positional timing errors occur between the balance being vertical and horizontal. A watch is usually in the horizontal position on your wrist during the day at work when you’re typing at a computer, and at night, resting on a table (with a folding buckle), it lies in the vertical position. To ameliorate the problem of these positional errors caused by gravity, Greubel Forsey inclined the balance in order to minimize the amount of time it stays in either the horizontal or vertical positions. The choice of 25 degrees (Tourbillon 24 Secondes) 30 degrees (Double Tourbillon 30° isn’t a random choice but the result of serious calculations and number crunching.
The Double Tourbillon 30° Technique won a first place finish in the 2011 International Timing Competition – Concours International de Chronometrie. You might ask why Robert and Stephen chose the Double Tourbillon 30° Technique for the competition. The answer is simply that it was around. It was a timepiecethat was supposed to go to a retailer. With confidence in all of their watches, they could’ve just as easily picked another.
Before going into competition or to a retailer, for that matter, a watchmaker needs to regulate the movement very precisely. It’s a more delicate procedure than you may think. Every adjustment affects something else; shifting one screw can throw everything off. As Stephen Forsey said, “It’s like moving towards a cliff in the dark without knowing where the edge is.” At some point you just have to be happy with what you’ve got.
Consider that Greubel Forsey only makes around 100 watches a year and only has a certain amount to choose from. A bigger company has several watchmakers working on many watches to get the best timing. They can communicate what is working in terms of adjustment versus what doesn’t so the others don’t go down the wrong path. For the 2011 Timing Competition, Greubel Forsey used one watch. The adjusting is much more precarious, so it’s even more remarkable that they won the timing competition. Coming in first justifies their raison d’etre, wouldn’t you say
You’ll notice the Greubel Forsey balances have different inclines.That’s because there’s a range that’s optimal for timekeeping and a comfortable size of the watch. In the new GMT, the 25° degree incline of the 24 second tourbillon also allows for a thinner watch than the 30° because of the reduced angle.
In terms of the tourbillon’s efficacy, I guess Grebuel Forsey can say: quod erat demonstrandum