Located at the foothills of the Jura mountains, just minutes away from watchmaking titans such as Omega and Rolex — is Armin Strom, a relatively young independent watch brand with impressive manufacturing capabilities befitting of the city they reside in.

First introduced in 2019, the Gravity Equal Force represents Armin Strom’s most wearable timepiece to date — and also has a few tricks up its sleeve. The company has manufacture status, meaning they design and produce at least one entire caliber of their own within their factory. This gives them the ability to research and develop innovative watchmaking technology. And for the Equal Force movement, Armin Strom developed a mechanism that represents a horological first, which we’ll discuss below.

Armin Strom Gravity Equal Force

System 78 

This Gravity Equal Force is the first watch within the System 78 collection, a line that will allow Armin Strom watchmakers to continue to explore new timekeeping methods. In speaking with Thierry Hess, Director of Marketing at Armin Strom, he mentioned that the company logo was slightly reworked prior to the launch of this timepiece, and “As you can see on the Gravity Equal Force, the lip (on the case at 6 o’clock) is still there but in a reduced form. And we also worked a lot on the overall design of the case. So the Gravity Equal Force is not just a new product, it also stands for the brand update and for a completely new collection.”

Armin Strom Gravity Equal Force

The Dimensions

Machined from 316L stainless steel, the official case diameter is listed as 41 mm but we measured the case and it’s actually slightly under 40.86 mm for all those that dwell on the precise proportions (myself included). With the highest point of the domed sapphire crystal included, top to bottom the watch is 12.93 mm thick, is neither too thick nor too thin. The watch may appear bigger than the measurements would suggest on the wrist, which is a general effect caused by a thin case band and bezel. Although considering the short 47.09 mm lug-to-lug length, it ultimately wears rather small — all relative to wrist size — and in our experience, numerous people we spoke with liked the dimensions compared to something larger.

Armin Strom Gravity Equal Force wristshot

The Crown

At 7.08 mm in diameter, the ridged crown is large enough to adjust the time and hand-wind the movement with ease, while not protruding into your wrist in a cumbersome way. The end of the crown has been hollowed out and then laser engraved with the Armin Strom emblem, then filled with matte white lacquer paint.

Armin Strom Gravity Equal Force

The Case

The short articulated lugs are first screwed to the case and then welded, and on our sample model, we did notice some minor brown marks (at high magnification only), around the welds where the lugs attach to the case. Having an interlug width that accommodates a 20 mm wide strap — the most universal size in modern watches — was a good choice. The included strap is hand made from thick black alligator leather and tapers from 20 mm wide at the lugs down to 18 mm at the folding clasp. The quality of the strap is excellent, although not everyone likes leather and I’d like to see this optionally fitted with an OEM textile strap or a steel bracelet as well.

Armin Strom Gravity Equal Force

The watch weighs just 89 grams with the included strap, which makes the watch more comfortable over extended periods compared to heavier watches. The lugs and case ergonomics also add to the overall comfort.

Armin Strom Gravity Equal Force

Using a fixed bezel, that’s been fully polished, from the top view it appears that the bezel and one-piece, but one look from the side and you can see the recessed caseband that aligns with the lugs and has a vertical brushed finish that contrasts the fully polished bezel — and enhances the premium tactile feel of the watch. You can also see the depth of the dial and movement components within the case, which has a three-dimensional look.

Armin Strom Gravity Equal Force

The Dial 

As with most Armin Strom watches, the movement is exposed not just on the caseback (or “movement side”) but also on the front. Set within the opening that also houses the movement components, is an off-center dial, another common design element seen on most Armin Strom watches. For the Gravity Equal Force, we reviewed the wine-red colored dial features a stamped guilloche pattern with printed Arabic numerals and chapter ring, with polished skeleton lance-shaped hour and minute hands. A small seconds overlaps the main dial at 7 o’clock. There’s no lume on the dial.

Armin Strom Gravity Equal Force

The three bridges you see on the right of the dial — inspired by pocket watches — are cut out on a wire eroding machine and completely hand decorated by Armin Strom watchmakers in Biel/Bienne. Each bridge is beveled and polished by hand before they go to the galvanic treatment to receive the rhodium plating. The jewel sinks and the screws are polished to a mirror finish. A frosted matte silver mainplate surface, visible on the dial side, contrasts the dial, bridges, mainspring barrel, and other components.

Armin Strom Gravity Equal Force

The Movement

“This state-of-the-art design creates a stable, low-friction axis of rotation for the mainspring to deliver power from the barrel arbor, supported by precision jewel bearings. Though using only a portion of the mainspring by preventing it from completely unwinding, Armin Strom still achieved a power reserve of 72 hours. Wound by a unidirectionally winding micro-rotor visible from the dial, the mainspring bears a power reserve indicator on the barrel cover for reference.”

Armin Strom Gravity Equal Force

The new automatic caliber ASB19
 beats at 3.5Hz (25,200 vph), is wound by a dial-side micro-rotor that winds unidirectionally, has 202 components, 28 jewels, and a 72-hour power reserve. In addition to the free-sprung balance wheel with 4 regulating screws,
 the movement has a Geneva-drive equal force barrel, and Geneva stop-work limited to 72 hours. The movement measures 35.52 mm x 11.67 mm and every component has been manually finished to a very high level.

Armin Strom Gravity Equal Force caliber ASB19

Horological Innovations

The Gravity Equal Force features three innovations. The first is the Declutch Stop-Work allows an automatic watch to operate with a more constant force. This is a watchmaking first. Claude Greisler, a Co-Founder of Armin Strom, highlights the improved usability “We have reinvented the whole functionality of an automatic watch movement to bring another level of precision and to offer our collectors more assurance for reliable daily wear.” Watch him explain the innovations in the video below.

The second innovation is a unique motor barrel (mainspring) design, called the Equal Force Barrel, that according to Armin Strom has clear advantages over the standard going barrel. Armin Strom designed a barrel operating in the reverse of a traditional mainspring barrel by driving the going train via the barrel arbor and winding the barrel housing, which both improves functionality and reduces wear.

Armin Strom Gravity Equal Force wristshot

A third innovation is the power reserve indicator, which is unconventionally mounted on the mainspring barrel cover. You can view the remaining power reserve — which is 72-hours when fully wound — as the barrel unwinds. The display is hidden when it rotates under the dial as you can see below. Still cool to have a readout of the remaining mechanical energy.

Armin Strom Gravity Equal Force


Armin Strom makes quality timepieces, in-house, and with the small volume per year it allows them to focus on quality over quantity, and many of the processes are done by hand as opposed to being made in a much more autonomous way like some of the neighboring brands such as Rolex.

Aesthetically, the System 78 blends traditional and contemporary elements, and while the watch wears like a larger modern dress watch, or smaller sports watch, I think with a simple strap change the feel could easily transition from a formal look to something casual.

Horologically, the motor barrel mainspring design, the stop-works declutch system (inside the mainspring barrel), and the reworked gear train provides equal force to the balance wheel and increases precision. Compared to prior Armin Strom collections, the Gravity Equal Force features enhanced wearability and aesthetics with a slimmer, smaller diameter case, and smaller bezel lip – while staying true to the brand’s open dial designs while offering a more classically appealing size.

The Armin Strom Gravity Equal Force System 78 is water-resistant to 30 meters and retails for $17,500 as shown in stainless steel with a black alligator leather strap. Armin Strom also offers a variety of bespoke customization options — and a select preview of different styles can be viewed online at the link below.

Learn more at Armin Strom.

Armin Strom Gravity Equal Force

Posted by:Jason Pitsch

Jason is the founder of Professional Watches and specializes in writing, product photography, and digital marketing.