Today, Swiss watch manufacture Armin Strom debuted an all-new timepiece featuring two horological innovations – inside their smallest watch case ever.

Presented in a 41 mm 
x 12.65 mm stainless steel case, with a reduced version of the brand’s signature lip (at 6 o’clock), the Gravity Equal Force is the first watch from the new System 78 collection, named for the two owners who were born in 1978.

On the wrist, the watch has the feel of a dressier watch compared to the company’s larger 44 mm timepieces, allowing it to easily slide under a cuff, but it also has enough size to look good on many wrists with short sleeves. It’s comparable in size to the Pure Force Resonance but is 1 mm smaller in diameter, which is a good thing.

Armin Strom System 78 Gravity Equal Force
Armin Strom System 78 Gravity Equal Force

A large off-center dial sits on the left side of the watch face, with three exposed horizontally brushed bridges on the right side, supporting the mainspring barrel, gear train, and automatic winding micro-rotor. The dial is shown in black but also comes in blue as well as a variety of custom color options. Printed Arabic numerals and a printed chapter ring coupled with polished, skeletonized lance-shaped stainless steel hour and minute hands (made in-house) indicate the time along with a small seconds dial overlapping the primary dial at 7:30. Behind the dial is a frosted plate, shown in silver, but also available in other variations. In addition to the hours, minutes, and small seconds there’s a small power reserve indicator on top of the mainspring barrel located in the lower section of the dial.

The case is available in stainless steel at launch, although other materials such as gold, titanium, and platinum will presumably be an option at some point. A fixed, polished bezel frames the top of the case, contrasted by satin-brushed flanks and lugs. A large push-in crown makes it easy to set and wind the watch, without being so large as to be cumbersome on the wrist.

Armin Strom Gravity Equal Force System 78 wristshot
Armin Strom Gravity Equal Force System 78 wristshot

On the back, you can view the Geneva stripes on the bridges, beveled and polished edges, and the perlage of the mainplate (also visible on the front side, and available in different custom finishes). The balance wheel is suspended by a bridge similar to the three on the front of the dial and features a premium free-sprung design.

That basically covers all the visuals, but Armin Strom is a true manufacture and accordingly, the Gravity Equal Force features an in-house movement. Not to mention two technological advancements that enhance the chronometry of the timepiece.

The first is a stop-work declutch mechanism combined with automatic winding for the first time, which results in consistent power delivery to the balance over the majority of the 72-hour power reserve. So you get a more consistent amplitude across the entire power delivery curve, thereby enhancing rate stability and chronometric precision.

According to Armin Strom, “Building upon the classic stop-works mechanism, Armin Strom developed an ingenious stop-works declutch system that operates inside the mainspring barrel to limit the torque delivered to the balance, providing smooth power delivery. This represents the first time a stop-works declutch mechanism has been added to an automatic winding movement.”

Armin Strom Gravity Equal Force System 78 wristshot
Armin Strom Gravity Equal Force System 78 wristshot

The second innovation is a new motor barrel design that according the manufacturer shows a clear advantage over the standard going barrel. Armin Strom watchmakers 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.

“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.”

The new automatic caliber ASB19
A 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 so-called Geneva-drive equal force barrel, and Geneva stop-work limited to 72 hours. It 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 System 78 caseback
Armin Strom Gravity Equal Force System 78 caseback

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.”

The Gravity Equal Force features enhanced wearability and aesthetics with a slimmer, smaller diameter case, smaller bezel lip, and a triplet of bridges inspired by pocket watches – staying true to the brand’s open dial designs while offering a more classically appealing size. Horologically, the motor barrel mainspring design, the stop-works declutch system (inside the mainspring barrel), and the reworked gear train which provides equal force to the balance wheel and increases precision provide a great improvement on a watch with the time and power reserve. Not to mention, this watch is now the most competitively priced timepiece within the entire Armin Strom collection.

The Armin Strom Gravity Equal Force System 78 is water-resistant to 30 meters and retails for $15,600 in stainless steel. (Ref. ST19-GEF.90.AL.M.35
)

Learn more at Armin Strom.

Jason Pitsch
Posted by:Jason Pitsch

Editor, writer, and photographer. View his archive here.