The Armin Strom Gravity Equal Force Ultimate Sapphire

Armin Strom recently presented a unique version of their much-praised Gravity Equal Force for this year’s Only Watch auction, and our team unanimously loved the direction Armin Strom took with that version. Now Armin Strom introduces the Gravity Equal Force Ultimate Sapphire that comes pretty close to that Only Watch edition. A highly technical timepiece that shows its intrinsic working in such a way that it becomes a proper watchmaking lesson on the wrist. 

What was always so spectacular with Armin Strom, is the way Serge Michel and Claude Greisler have shaped the brand since they took it over from Mr Armin Strom, the brand’s namesake. Armin Strom, a watchmaker and engraver, always engraved his watch and with that, he also took away a lot of superfluous material. This meant that his watches were not only engraved but often ‘heavily’ skeletonized. The result is that the owners of his watches could perfectly see how the watches work. You could easily see which wheel turned which next wheel and this way follow the flow of energy through a movement. When Serge Michel and Claude Greisler took over, they did not apply a similar way of engraving or skeletonizing, yet their new in-house developed, manufactured, finished and assembled movements still perfectly show how the movement works; this is why we’ve been calling their watches “a watchmaking lesson on the wrist” since the very beginning.

The new Gravity Equal Force Ultimate Sapphire features a beautiful backdrop for the gears and bridges; the movement’s black plate features a guilloche pattern that was “created by hand by the celebrated Finnish watchmaker Kari Voutilainen“. I’m guessing here, but I think the initial design for the movement’s main plat was created by Kari Voutlainen, however, all 20 plates are more likely to have been engraved at Voutlainen’s dial manufacturer Comblémine (who did dials for Armin Strom – and others – before.)

A new feature we first saw on the unique piece for Only Watch is the grey-toned sapphire dial, which offers an even better view of the mechanics inside than before. The mainspring barrel and micro-rotor are both kept down by dark grey ruthenium coated bridges, while the micro-rotor and barrel themselves are rhodium coated. This creates a beautiful monochromatic piece of mechanical artistry that is simply magnificent to witness and recalls the words “fifty shades of grey.”

As a concise reminder of what the watch’s name actually means, or what it stands for, you first have to know that every mechanical watch is powered by a spring, the mainspring, that slowly unwinds and turns the gears and hands. When that mainspring is fully wound the torque is strong and when the spring is almost fully unwound, the torque is much less strong. Because of this variation in torque, it is difficult to regulate a watch and often, with watches with a very long power reserve from one mainspring, the watch is regulated to an average. But this is of course a sub-optimal, but often affordable, solution.

In order to regulate a watch very precisely, a stable torque is what you need. While there are several pretty expensive and complex solutions, in the shape of constant force devices like a ‘chain a fusée’ or a ‘remontoire’, there are also more affordable solutions that come pretty close to what you’d want.

I’m talking about a Geneva stop work mechanism, which prevents the mainspring from fully unwinding, and thus it cuts off the extreme low torque from further unwinding. The result is that power delivered is the most consistent part of the full mainspring, so that the delivered torque is reasonably stable. But… the downside of this solution is that it does not work on the mainspring barrel of an automatic watch! It works perfectly in for instance Karsten Fräßdorf’s Tourbillon Spirograph Sport that has a hand-wound movement.

While a stop-work solution is being used by a handful of high-end watches, already for centuries, a similar solution for an automatic watch had not been found. That is, until late 2019 when Armin Strom presented the Gravity Equal Force. Armin Strom managed to find a solution and now their mainspring barrel is equipped with a stop-work that prevents the mainspring from fully unwinding. So the torque delivered to the movement is pretty stable and the watch can be regulated rather precise over the full 72 hours of running time. All of that is housed in the same 41mm diameter stainless steel case as before, with a minimalistic look.

Claude Greisler, Armin Strom’s co-founder and head watchmaker, calls the new watch’s design “cool, understated monochrome”. Heck, we couldn’t agree more! Serge Michel, founder of Armin Strom adds that the Gravity Equal Force will be limited by production capacity and they hope to be able to produce 30 more watches next year in addition to the 15 from this year.

The Gravity Equal Force Ultimate Sapphire will be available from October 2021 in a limited quantity of 15 pieces for 2021, at a price of CHF 22,900 or EUR 20,000. Due to the limited production capacity, the special timepiece will be available subsequently in a very small number of pieces per year. More info at www.arminstrom.com.