When observing the landscape of modern independent horology, few manufactures manage to bridge the gap between rigorous mechanical innovation and distinct aesthetic flair quite like Armin Strom. The release of the Gravity Equal Force Ultimate Sapphire Salmon, reference ST24-GEF.SAL, marks a significant moment where these two philosophies do not just meet but actively collaborate. This timepiece is not merely a color refresh; it represents a sophisticated evolution of the System 78 collection, bringing a warmth and textural depth to a platform previously defined by its cool, industrial technicality. The choice of a salmon-colored mainplate is a deliberate nod to a hue that has historically signaled a special distinction in watch collecting, yet here it is executed with a modern PVD coating and traditional guilloché that roots the watch firmly in the twenty-first century while acknowledging the past.
The immediate visual impact of the Gravity Equal Force Ultimate Sapphire Salmon is defined by the striking contrast between the warm, copper-pink tones of the mainplate and the cool, monochromatic austerity of the mechanics that float above it. The dial side of this watch is a lesson in architectural depth. Rather than a traditional full dial that hides the engine, the face of the watch is an open arena of gears, bridges, and springs. The dominant feature is the triplet of horizontal bridges on the right side of the case, which hold the micro-rotor, the gear train, and the mainspring barrel in place. These bridges, finished with straight graining and polished bevels, provide a structural rigidity to the design, looking almost like girders in a modernist building. Beneath them, the salmon mainplate radiates with a mesmerizing texture. This is not a simple flat color; the surface features a hand-guilloché pattern created in collaboration with the renowned independent watchmaker Kari Voutilainen. The pattern catches the light in shifting waves, adding a level of organic tactility that softens the harsh lines of the mechanical components.
Courtesy of Armin Strom
To understand the significance of this release, one must look at the history and trajectory of the
Armin Strom brand itself. Founded in 1967 by Mr. Armin Strom, the company initially built its reputation on the art of hand-skeletonization. For decades, the name was synonymous with taking existing movements and carving away the excess material to reveal the inner workings. However, the revitalization of the brand in 2009 under the stewardship of Serge Michel and Master Watchmaker Claude Greisler marked a pivot toward becoming a fully integrated manufacture. The goal shifted from simply beautifying existing engines to designing, developing, and manufacturing their own proprietary calibers. This philosophy, which they term the "Science of Movement," is the bedrock upon which the Gravity Equal Force is built. The System 78 collection, to which this watch belongs, was conceived as an entry point into their world of high horology, yet it spares no expense in terms of finishing or mechanical ingenuity.
The "Gravity Equal Force" name itself is a direct reference to the primary technical challenge this watch seeks to resolve: the inconsistency of power delivery in a mechanical watch. In a standard mainspring barrel, the torque provided to the escapement is highest when the watch is fully wound and drops significantly as the spring unwinds. This variance in torque can lead to fluctuations in the balance wheel's amplitude, which in turn affects the watch's accuracy—a problem known as isochronism. To combat this, Armin Strom engineered the Calibre ASB19, the first automatic watch to feature a "stop-work" declutch mechanism combined with a micro-rotor. This stop-work mechanism, often referred to historically as a Geneva stop-work, limits the rotation of the mainspring barrel. It prevents the spring from being wound too tightly and, crucially, stops the barrel from unwinding past the point where torque drops off significantly. By utilizing only the central, most consistent portion of the mainspring's power curve, the movement ensures that the balance wheel receives a steady, equal flow of energy throughout the entire 72-hour power reserve.
Visually, this technical prowess is displayed with a transparency that borders on exhibitionism. The mainspring barrel is prominently visible at the 5 o'clock position on the dial side. Because the cover is open, the wearer can actually see the coils of the spring and the stop-work mechanism in action. Watching the mechanism engage is a treat for the mechanically inclined, offering a dynamic display of the energy storage that usually remains hidden in conventional timepieces. Situated just above the barrel, at the 1 o'clock position, is the micro-rotor. While most automatic watches hide the rotor on the back, Armin Strom has brought it to the front, allowing it to become a part of the visual drama. As the wearer moves their wrist, the rotor spins, capturing kinetic energy to wind the barrel. The interplay between the spinning rotor and the static bridges creates a lively animation on the wrist, constantly reminding the owner that the machine is alive and functioning.
Courtesy of Armin Strom
The time-telling function is handled by an off-center dial located on the left side of the watch face. For the "Ultimate" edition, this subdial is crafted from a grey-toned sapphire crystal. This choice of material is inspired. A solid dial would have blocked the view of the mechanisms underneath, but the smoked sapphire allows for a ghostly transparency. One can peer through the chapter ring to see the keyless works and the setting gears, yet the grey tone provides enough contrast against the salmon background to ensure that legibility is not compromised. The hands are rhodium-plated, faceted, and polished, filled with Super-LumiNova to ensure visibility in low light. The stark, silver tone of the hands cuts sharply against the grey sapphire, ensuring that despite the complexity of the background, reading the time remains intuitive. The layout of the subdial, with its printed white minute track and applied indices, retains a technical, instrument-like quality that balances the artisanal nature of the guilloché plate.
The case that houses this mechanical metropolis is crafted from stainless steel and measures a contemporary 41 millimeters in diameter. With a height of 12.65 millimeters, it has a substantial presence without being overbearing. The lug-to-lug distance of 48.09 millimeters ensures that it sits securely across a variety of wrist sizes. The design of the case is characteristically Armin Strom, featuring the brand's signature "lip" at 6 o'clock, which dates back to the days when customers could have their initials engraved there. The lugs are open-worked, continuing the theme of transparency and lightness. The bezel is thin and polished, maximizing the opening for the dial and allowing the movement to take center stage. The case finishing is a mix of brushed and polished surfaces, creating a play of light that accentuates the architectural lines of the silhouette. Water resistance is rated at 3 ATM, which is standard for a dress-oriented piece of high horology, indicating that while it can withstand splashes, it is not designed for aquatic adventures.
Turning the watch over reveals the back of the Calibre ASB19 through a sapphire crystal case back. While the front of the watch is dominated by the kinetic elements of the winding and power storage, the back offers a view of the regulation system and the sprawling bridges. The movement dimensions are 35.52 millimeters by 11.67 millimeters, filling the case back nicely. The large bridge that covers the top half of the movement is finished with broad Geneva stripes that radiate outwards, guiding the eye toward the balance wheel. The balance wheel oscillates at a frequency of 3.5 Hz, or 25,200 vibrations per hour, a beat rate that offers a good compromise between stability and service intervals. The movement contains 28 jewels and is comprised of 202 individual components. The finishing on the back is just as meticulous as the front, with black polished screws, deep circular graining on the mainplate, and hand-chamfered edges on all bridges. The "Equal Force" and "System 78" engravings are executed with precision, reinforcing the identity of the caliber.
Courtesy of Armin Strom
One of the most impressive aspects of Armin Strom’s production process is their commitment to double assembly. In an industry where efficiency is often prioritized, Armin Strom assembles every single movement twice. The watchmakers first assemble the movement to ensure that all parts fit perfectly and function as intended. They then completely disassemble it, clean every component, and proceed with the final assembly and lubrication. This arduous process ensures that no compromises are made in the final product and that the tolerances are held to the absolute tightest standards. This level of dedication is palpable when handling the watch; the winding action is smooth, the setting of the hands is precise, and the overall operation feels solid and reassuring.
The collaboration with Kari
Voutilainen for the mainplate decoration elevates this specific reference into the realm of "Ultimate." Voutilainen is widely considered one of the greatest living watchmakers, particularly renowned for his finishing and dial work. The guilloché pattern on the salmon plate is not merely stamped; it is engine-turned by hand. This traditional technique involves carving geometric patterns into the metal using a rose engine lathe, a process that requires immense skill and patience. The specific pattern chosen for this watch features intersecting curves that create a sense of movement and vibration, echoing the oscillation of the balance wheel. The salmon color itself is achieved through PVD (Physical Vapor Deposition) coating, ensuring a uniform and durable hue that will not fade over time. The juxtaposition of Voutilainen’s classical guilloché with Armin Strom’s modern, industrial movement architecture creates a tension that is incredibly compelling. It is a meeting of old-world craftsmanship and new-school engineering.
Completing the aesthetic package is the strap, which has been carefully selected to complement the tones of the watch head. The Gravity Equal Force Ultimate Sapphire Salmon comes mounted on a grey nubuck leather strap. Nubuck, with its sanded, velvet-like surface, offers a softer and more contemporary look than traditional alligator leather. The grey tone of the strap picks up the grey of the sapphire dial and the steel of the case, tying the entire color palette together. It features matching grey stitching and keepers, maintaining a monochromatic look that allows the salmon mainplate to pop even more. The strap is secured with a stainless steel double-folding clasp, which provides security and comfort on the wrist. The choice of a folding clasp over a pin buckle also helps to preserve the life of the leather strap by reducing the bending and pulling required to put the watch on.
The wearing experience of the Gravity Equal Force is unique due to the layout of the movement. Because the micro-rotor and barrel are on the dial side, the watch has a distinct visual weight and balance. On the wrist, the 41mm diameter feels modern and assertive. The open-worked lugs help the watch hug the wrist, and the relatively short lug-to-lug distance prevents it from overhanging. The view when checking the time is multi-layered. First, the eye registers the time on the off-center dial. Then, the gaze drifts to the right, catching the shimmer of the salmon guilloché. Finally, the focus settles on the mechanical details—the rotation of the micro-rotor, the slow creep of the mainspring barrel. It is a watch that demands interaction; it is difficult to simply glance at it without getting distracted by the depth of the display.
Courtesy of Armin Strom
The concept of transparency that Armin Strom champions is not just literal but metaphorical. By exposing the stop-work mechanism, the brand is transparent about how the watch achieves its precision. There is no "black box" magic here; the engineering solution to the problem of isochronism is laid bare for the owner to understand and appreciate. This educational aspect is a key part of the appeal for collectors who are interested in the "how" and "why" of watchmaking. The Gravity Equal Force does not just tell time; it explains the physics of its own operation. The addition of the "Ultimate" designation implies that this version represents the pinnacle of the model's potential, and the inclusion of high-end métiers d'art finishing on the mainplate certainly supports that claim.
In the broader context of the watch market, the Gravity Equal Force occupies a very interesting niche. It competes with other high-end independent brands that focus on open-working and technical innovation, yet it offers a specific feature set—the automatic winding with stop-work—that is unique. The fusion of the salmon colorway, which has seen a surge in popularity in recent years, with the technical grey and steel elements, makes for a very versatile aesthetic. It is dressy enough to be worn with a suit, thanks to the guilloché and the modest height, but technical and robust enough to be worn in a casual setting with the nubuck strap. It avoids the stuffiness of a traditional dress watch while offering far more refinement than a standard sports watch.
The rarity of this timepiece cannot be overstated. Armin Strom has capped the production of the Gravity Equal Force Ultimate Sapphire Salmon at just 25 pieces per year. This low production number is a result of the extensive hand-finishing required for each movement and the specialized nature of the guilloché work provided by Voutilainen’s workshop. Owning one means joining a very exclusive club of collectors who appreciate the nuances of independent watchmaking. It guarantees that one is unlikely to ever encounter another person wearing the same watch at a dinner party or business meeting. This exclusivity is a significant factor in the value proposition, offering a level of rarity that mass-market luxury brands simply cannot match.
Courtesy of Armin Strom
Pricing for this masterpiece of engineering and art is set at $36,000 USD. While this is a significant sum, it must be weighed against the content of the watch. When one considers the in-house movement development, the patented technical innovations, the collaboration with Kari Voutilainen for the hand-guilloché plate, and the sheer level of hand-finishing on every component, the price becomes contextualized within the high-horology landscape. Many watches at this price point rely on stock movements or simple modular additions; Armin Strom offers a fully integrated, ground-up architecture designed specifically for this model. The value here is derived from the tangible hours of skilled labor and the intellectual property inherent in the movement design.
Availability is naturally constrained by the limited production run. With only 25 units being produced annually, prospective buyers will likely need to have a relationship with the brand or an authorized retailer to secure an allocation. This scarcity ensures that the Gravity Equal Force Ultimate Sapphire Salmon will remain a rare bird in the wild, a timepiece that signals a deep appreciation for the science of movement and the art of fine finishing. For the collector who values transparency, mechanical ingenuity, and distinctive aesthetics, this salmon-dialed wonder offers a compelling argument for being the ultimate expression of the Gravity Equal Force concept.
Case: Stainless steel construction measuring 41 mm in diameter, 12.65 mm in height, and 48.09 mm lug-to-lug; equipped with sapphire crystal and case back with anti-reflective treatment; water resistant to 3 ATM.
Movement: Armin Strom Manufacture Caliber ASB19 automatic winding with micro rotor; features a patented equal force barrel and Geneva stop-work with a 72-hour power reserve; operates at 3.5 Hz (25,200 vph) with 28 jewels and 202 components; mainplate is Salmon PVD with guilloché pattern by Kari Voutilainen.
Dial: Grey toned off-center sapphire crystal subdial; rhodium hands are facetted, polished, and filled with Super-LumiNova®.
Strap: Grey nubuck strap with grey stitching and keepers; secured by a stainless steel folding clasp.
Price: $36,000 USD
Reference Number: ST24-GEF.SAL
Notes: Limited annual production of 25 pieces per year; the first movement to feature a stop-work declutch mechanism inside the barrel combined with a micro rotor; mainplate decoration created in collaboration with Kari Voutilainen.