The Greubel Forsey Double Tourbillon 30° Technique: What’s Friction Got To Do, Got To Do With It!?


Hopefully that loud bang didn’t startle you too much! If it did, take a moment to go watch a video of a cute kitten and come back when you have calmed down a bit. Better? Ok! Here at the beginning of the new year, I am reminded there is a lot of advice out there saying you should always start with a bang.

It seems those words of wisdom have been around quite a long time. Take a look at sporting events; many are initiated with a gunshot. A little forceful don’t you think? The 24 Hours of Le Mans begins with a foot race across the speedway, and the Ironman Triathlon begins with a grueling 2.4-mile swim preceded by a mad dash into the ocean. Crazy!

But what else begins with a bang? Well, a lot of things, including almost every major war; the creation of new land by volcanoes; and the biggest bang of a beginning: our universe! Regardless of your views on that, it still must have been a pretty big, impressive bang.

Greubel Forsey Double Tourbillon Technique in platinum

Greubel Forsey Double Tourbillon 30° Technique in platinum

What does beginning with a bang have to do with anything? Honestly, not much. But for my topic today, I wanted to start with a bang and discuss a piece that I feel exploded onto the scene and whose effects we are still feeling today. I would be speaking of none other than the incredibly intriguing Greubel Forsey Double Tourbillon 30° Technique, a/k/a the “Oh My Goodness.”

I may have made up that alias (though you were all thinking it), but the Double Tourbillon 30° Technique may be the most impressive Greubel Forsey I have seen emerge from that workshop.

Of course, that is saying something when EVERY piece that comes from its atelier is mechanically exquisite. Come to think of it, the atelier itself is also pretty exquisite…I think I see a pattern forming. Nevertheless, the Double Tourbillon 30° Technique stands out among the brand’s pieces for a couple reasons, one of which deserves much more consideration after a certain friendly competition where it amassed a record score and eliminated all doubt about its perfection.

But we’ll get to that later. First I want to go over the reasons I wake up in a cold sweat after dreaming about the Double Tourbillon 30° Technique, and they are many. Firstly, and most importantly if you are to know why I love these things called watches, is the fact that I ADORE mechanical complexity disguised as simplicity and it being given ample room to spread its wings of wonder over the viewer.

Dramatic maybe; accurate yes! The Technique does what most other watches can only hope to achieve; it gives you a stadium of giants to play in thanks to the creative discretion of Robert Greubel and Stephen Forsey.

Greubel Forsey Double Tourbillon Technique 8927

Greubel Forsey Double Tourbillon 30° Technique

When Greubel and Stephen Forsey were designing the Technique, they knew that they wanted to emphasize the movement and the functions as much as possible (I don’t disagree), but didn’t want to take the traditional path of simply making a skeletonized watch.

With traditional skeletonization, the architecture is opened up and reduced to a minimum, but still left in a flat plane with very little increased depth. For the Double Tourbillon 30° system, that simply wouldn’t work as it is more properly viewed from all angles given its awesome three-dimensional nature!

So an entirely new movement was designed from the ground up with inspiration coming from many places in the industrial world and even partly from something very near and dear to Greubel Forsey: Meccano construction sets. Towers and bridges became the backbone of the Technique allowing for incredible depth and copious amounts of space to view the inner workings.  Looking at the Double Tourbillon 30° Technique, I think it’s clear that the inspirational new direction paid off!

It’s openness also lends a sense of clean and purposeful simplicity. We know that it is more complicated than it appears, but the towering walls and long spans of the bridges mirror things we see standing in our everyday lives, and that connection seems familiar and easy. A bridge over a river in your city looks simple, but the engineering and construction of them are anything but easy.

That is the absolute genius behind the construction of the Technique: the robust, precise parts that sit on many different levels, giving depth and weight to the mechanism, all the while casting a veil over the reality of the extreme complexity with which this movement works. The only indication is that canted tourbillon spinning around at the bottom. But we’ll get to that later. Glorious suspense!

So with a three-dimensional dial and large components out in the open comes an issue that would hinder many other watch companies, but to Greubel Forsey, it’s just another day in the office. I am talking about finishing, and the INSANE level to which Greubel Forsey takes each and every part.

Greubel Forsey Double Tourbillon Technique 8925

Greubel Forsey Double Tourbillon 30° Technique

While many companies and independents do have amazing finishing, only a few are close to the thoroughness and quality of the GF pieces. Greubel and Forsey both spent considerable time working at Renaud et Papi (APRP), a superstar movement think tank in its own right, which fostered a culture of perfect and precise finishing and mechanics. Because of this, every part that goes into a Greubel Forsey watch is meticulously hand-finished, no matter where it is located, seen or unseen, in the movement. With so many exposed sides, edges, and faces there is a lot of room to add the “finishing” touch to the components. By the way, I consider myself a pretty “punny” guy. Told you.

Seriously, though, there is a lot going on with the finishing: beveled edges, straight-grained surfaces, circular-grained faces, snail-grained surfaces, polished bevels, polished surfaces, blasted satin finishes, blasted coated finishes, polished coated finishes, heat bluing, gold plating, and finally an etched and printed sapphire hour ring creating ever more depth. Taking enameling and miniature painting out of the mix, they pretty much have it all. I would have to say it shows!

With the depth created, the mechanics visible, and the finishing applied, this watch is completely stunning visually and needs no further fawning. But I don’t rest on my laurels, so what was I on about earlier regarding a friendly little competition? And, oh boy, that competition is actually some of the biggest real news in the watch industry in the last 30 years, nay, almost 40 years! With the advent of quartz watches in the middle part of this century, a 200-plus-year history of chronometer trials was abandoned as it seemed the idea was pointless with the new super accurate (and super cheap) timepieces flooding the market.

Greubel Forsey Double Tourbillon Technique on the wrist 8912

Greubel Forsey Double Tourbillon 30° Technique on the wrist

Concours International de Chronométrie

You may remember reading about this in Ian’s post about why accuracy matters. Well, fast forward to 2009 and the Concours International de Chronométrie was established, thus reviving the storied tradition of testing watches side-by-side for accuracy and bragging rights.

This brings us to 2011 and the second biennial Concours International de Chronométrie, and what a concours it was! Random language-nerd side note: concours comes from French and means “competition or contest.” And you thought learning a new language was hard! Greubel Forsey entered the Double Tourbillon 30° Technique in the tourbillon class and waited for the results.

Three 15-day test periods later, and what I can only assume were some terribly chewed-on fingernails, the results were released with great elation. The Double Tourbillon 30° Technique had won its category, topped the previous winner (a Jaeger-LeCoultre Master Tourbillon, which received 909 points) and set the record for the highest score achieved by any timepiece in its trials with a total score of 915 out of 1000!

Granted, it was only the second competition so that record is from a small field, but it still bested something that outshone many other watches and was considered super accurate itself!

Greubel Forsey Double Tourbillon Technique 8926

Greubel Forsey Double Tourbillon 30° Technique

A tourbillon developed specifically for the wristwatch

But why is that such a big deal, it was just one tourbillon beating another tourbillon, right? Wrong. It was a unique design that incorporated ideas that Greubel and Forsey invented with a double tourbillon on an incline of 30 degrees that they believed from the beginning solved many problems with the basic tourbillon.

Now you might be thinking, “What were these problems, because I thought the tourbillon was invented to cancel out the effects of gravity, thus creating a more accurate timepiece, or am I wrong?” Naturally, you would be correct in your thinking. But the tourbillon was invented when the only timepieces were pocket watches, and there is the rub.

Any watchmaker that has regulated a movement knows firsthand why the tourbillon was invented, and why it is generally considered Not Applicable for Wristwatches. So what’s the reason of the season? Friction. You probably didn’t think that title was going to come back around, did ya!?

One of the greatest factors in determining the variability of the rate in a watch is the friction on the balance staff caused by rubbing in its pivots. The position that contains the least amount of friction is usually considered dial side up, or whatever position allows the balance to be pivoting perpendicular to earth’s gravity. That means standing straight up, only spinning on the tip of its staff, with the least amount of its surface area rubbing against the jewels.

Greubel Forsey Double Tourbillon Technique. Photo courtesy Malik Bahri.

Greubel Forsey Double Tourbillon Technique. Photo courtesy Malik Bahri.

Mantel clocks, pocket watches and wristwatches

For a mantel clock or carriage clock, that was the preferred position since it stayed in that orientation and could be regulated for that one position. But for pocket watches, the balance was almost always not in a dial-up position but instead in a crown-up position, hanging on a chain. This meant that the balance was constantly rubbing on the side of its staff, on both the top and bottom. While the balance spins almost completely around considering the amplitude in both directions, the spring is fixed which means the balance staff will always rub in the same, non-symmetrical way. That’s a problem, one that the tourbillon was invented to fix. The rotating cage of a tourbillon made sure that the balance rubbed evenly over a period equaling out the downward forces creating friction. Problem solved. Sort of.

The tourbillon worked brilliantly for the same reason carriage clocks keep great time, because it really only needed to be regulated for one position. This is because pocket watches hang for a majority of their life, always in the crown-up position (also the reason why pocket watch stands exist, true story).

With the invention of wristwatches came the truly mobile timekeeping device, moving to one of a thousand positions throughout the day, with extended time being in the dial-up position (hand resting on a table) and possibly vertically with the hand resting at one’s side. This created tough spots to regulate for as the rates vary wildly between balance perpendicular to gravity and parallel to gravity due to vastly different amounts of friction.

A regular tourbillon does not solve this issue in a wristwatch. Some solutions have been proposed with multi-axis tourbillons spinning in multiple directions. They worked well, but Greubel Forsey had other ideas.

Friction on the balance staff

The duo realized that the main problem was controlling friction and needing to compensate for when the balance switched from most positions to straight vertical, only spinning on the end of its staff with the lowest amount of friction possible.

To this, they realized that if they tilted the axis of the balance by 30 degrees and set that spinning in a tourbillon, it could hold the balance in a constant state of comparable friction, thus allowing more accurate regulation. The chances of the watch being located at precisely 30 degrees so that the balance staff would be vertical are drastically reduced and any natural resting position would put the watch back into a well-regulated state. Boom! Scienced!

Greubel Forsey Double Tourbillon 30° mechanism

Greubel Forsey Double Tourbillon 30° mechanism

Before the Concours International de Chronométrie trials, this idea was still considered theory by the general population of watch nerds. But after the results were revealed, Greubel and Forsey stood vindicated in their invention, not to mention that they had an incredibly sexy timepiece as well. I guess you could say that is just icing on the cake, either a sexy cake or an accurate cake depending on which is more important to you, but icing on the cake just the same.

In the the video above, Robert Greubel, Stephen Forsey and the team responsible for winning the 2011 chronometry competition explain their approach.

The Double Tourbillon 30° Technique is simply an amazing timepiece in every sense of the word. It stands out among giants and has gone down in the history books as one to be remembered.

What have we here now??? Ahh, it’s my own little brand of evaluation, where the categories are made up and the points don’t count. Except for Awesome points. Those count.

First, here are the categories with their explanations.

·       Wowza Factor * The ability of a watch to make you pause, stare, choke on your spit and say “wow” out loud.

·       Late Night Lust Appeal * The way that, no matter how late at night it is, if you come across a photo, article, or ad for a particular watch, you will lose the next 20 minutes of your life as you fall down the rabbit hole.

·       M.G.R. (Movement Geek Rating) * A number between 1 and 74 for the awesomeness of the movement based on clever mechanisms, novel usage, and sheer audacity in finishing. (Quartz need not apply.)

·       Added-Functionitis * The inflammation of a watch with complications and secondary features requiring immediate and liberal application of Gotta-HAVE-That ointment (sold over the counter in your local pharmacy).

·       Ouch Outline * A scale between 1 and stepping on a Lego for the amount of pain you would endure to be able to purchase the timepiece. (May or may not be related to suggested retail price.)

·       Mermaid Moment * The approximate time it will take a watch that might not score well on the Wowza Scale to turn from a manatee into a beautiful mermaid of a watch.

·       Awesome Total * The aggregate sum of all Awesome points available, which determines how much Awesomazingatude a timepiece has.

So how did the Greubel Forsey Double Tourbillon 30° Technique, a/k/a the “Oh My Goodness,” do on my scale?

Wowza Factor * 10 I said we would start off with a bang and with a scale-topping number like that. You can bet I was wowed when I first laid eyes on the Technique!

Late Night Lust Appeal * 214 gn » 2,098.623 m/s2 A mighty hefty force holding your butt down, which will keep you staring for hours! Only one person has survived this amount of G-forces, but they never saw this watch!

M.G.R. * 73.2 This movement makes lesser movements ask for its autograph. That is if it could hold a pen. Which it can’t. But it can be Awesome like nobody’s business!

Added-Functionitis * Moderate With a power reserve function, the Technique contains a very useful added complication. But this category doesn’t play favorites, so I will recommend OTC-strength Gotta-HAVE-That cream for the basic but comfortable horological swelling.

Ouch Outline * 12.6 – Stubbing Your Toe in the Dark Searching for the Light Switch Everyone has had that pain, and for some reason the bleak blackness of night makes that stubbed toe all the more painful. But I would stub my toe every night if it meant having the Technique keeping super accurate time on my wrist while I groaned in the dark!

• Mermaid Moment * Hey that reminds me of Meccano! The look, the feel of cotton! I mean, uh, the sight of a Greubel Forsey Double Tourbillon 30° Technique on the wrist, or the sight of those dial components standing resolute, that’s when I called the priest!

• Awesome Total * 915 It seems appropriate that the Awesomazingatude points should reflect Greubel Forsey’s record-setting score for chronometric perfection!

For more information on Greubel Forsey, please visit

Quick Facts:
Case: 48 x 17.7 mm; available in white gold, red gold, black titanium, and platinum
Movement: manual winding Caliber GF02, 3 Hz/21,600 vph frequency, four coaxial serially operating fast-rotating barrels, power reserve 120 hours; inner tourbillon inclined at 30° and rotating in 60 seconds; outer tourbillon rotating in four minutes
Functions: hours, minutes, seconds; power reserve indicator

16 replies
  1. Timothy Treffry
    Timothy Treffry says:

    Enjoyed your explanation of the virtues of the inclined tourbillon, but at first sight the argument seems to lead to 45 degrees rather than 30. I guess you may argue that 45 would be only be optimal if the watch spent equal time dial up and on edge (in the physical sense). The proportion of time spent in these positions is surely very sensitive to the life style of the wearer.
    I guess I am also a Nerd (Elizabeth could confirm this).

    • Ian Skellern
      Ian Skellern says:

      Hello, Timothy, and thank you very much for that pertinent observation. In theory you are, of course, correct that a 45° angle would be optimal, but Greubel Forsey’s aim was to develop a tourbillon for the wristwatch. And as you are well aware, a wristwatch movement is an exercise in compromises.

      A tourbillon inclined at 45° would make the movement higher – unacceptable higher for Rober Greubel and Stephen Forsey – and there are more frictional loses incurred in transmitting a force through 45° than 30°.

      A 45° inclined tourbillon would be theoretically better, but Greubel Forsey’s research led them to believe that a 30° inclined tourbillon offered more practical benefits while still offering excellent performance. Excellent enough for their Double Tourbillon Technique with its 30° inclined tourbillon to be the reigning champion at the modern Chronometry Competitions held by the Watchmaking Museum in Le Locle.

        • Ian Skellern
          Ian Skellern says:

          This is just off the top of my head, but I think that no matter how you do it, changing the direction of a force requires force and the larger the change of direction (or angle) the larger the force required to change its direction. That increased force will result in higher friction losses through the gear teeth and bearings.

          You have got me interested to look deeper into the physics and maths involved, though. Do you think otherwise?


Trackbacks & Pingbacks

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  3. […] A Greubel Forsey Double Tourbillon Technique holds the record as the most independently tested precise wristwatch and it has a balance beating at a relaxed 3 Hz (see The Greubel Forsey Double Tourbillon 30° Technique: What’s Friction Got To Do, Got To Do With It!…). […]

  4. […] Holy Grail of such rare timepieces is the Greubel Forsey Double Tourbillon 30° Technique (see The Greubel Forsey Double Tourbillon 30° Technique: What’s Friction Got To Do, Got To Do With It!?). But the Technique has one major drawback for me: its 48 mm case diameter makes it too large for […]

  5. […] the Double Tourbillon Technique. It set a benchmark score that still has not been beaten: read The Greubel Forsey Double Tourbillon 30° Technique: What’s Friction Got To Do, Got To Do With It!… for the full […]

  6. […] the pieces that feature movements specifically designed to showcase all the parts from one side (Greubel Forsey Double Tourbillon 30° Technique anyone?), which are about as exhibitionist as it gets. But the thing that makes the […]

  7. […] And for Joshua’s look at the 30° tourbillon, please read The Greubel Forsey Double Tourbillon 30° Technique: What’s Friction Got To Do, Got To Do With It!… […]

  8. […] For more information, please read The Greubel Forsey Double Tourbillon 30° Technique: What’s Friction Got To Do, Got To Do With It!… […]

  9. […] Competition organized by the Horological Museum in Le Locle with a score of 915/1,000 points. Read The Greubel Forsey Double Tourbillon 30° Technique: What’s Friction Got To Do, Got To Do With It!… for more on […]

  10. […] All I can say is whoa. Whoa to the gyroscopic escapement of the Zero-G, whoa to the triple-axis tourbillons that now number almost a handful, and whoa to the double-axis tourbillons, one of which is the most accurate watch ever to compete in the Concours International de Chronométrie. You may remember the Greubel Forsey Double Tourbillon Technique took top honors in 2012 with a record-setting score of 915 points out of 1000. (See The Greubel Forsey Double Tourbillon 30° Technique: What’s Friction Got To Do, Got To Do With It!) […]

  11. […] please be sure to read about my article about the Double Tourbillon 30° that took top prize at the Concours International de Chronométrie and check out Greubel Forsey’s other awesomazing […]

  12. […] To read Joshua’s very first article for Quill & Pad, please click “What’s Friction Got To Do, Got To Do With It!?” […]

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