Armin Strom Specialists

The brand's own history starts with the watchmaker Armin Strom, who opened a shop in Burgdorf in 1967, selling and restoring watches before he became known for hand-skeletonized movements. The skeletonizing removes material from the plates and bridges to reveal the mechanism, and the parts that remain are decorated by hand. The company that carries his name today traces its founding to 2009, when Serge Michel and Claude Greisler set up the manufacture in Biel/Bienne.

The manufacture is the basis for the modern range. Armin Strom's System 78 collection introduced the Gravity Equal Force in November 2019, and the Resonance collection brings the Mirrored Force Resonance and other models built around a dual-regulator design. The brand describes the Resonance technology as patented, and its calibers are described as in-house automatic and manual movements.

For an owner, the practical point of the history is that the company is young compared with most Swiss houses. Its calibers are recent designs, so ask about parts before you commit to a long repair. Ask the brand what it can supply for the reference you own before you commit to a long repair.

The Mirrored Force Resonance debuted in 2016 with two regulating systems, each with its own energy source and gear train, linked by a patented resonance clutch spring. The spring is designed to bring the two balances into a synchronized rhythm, and the watch shows the result with two seconds displays that a pusher resets. The brand's claim is greater rate stability, and it is a claim about the mechanism rather than a promise of absolute accuracy against a reference clock.

The Gravity Equal Force, introduced in 2019, takes a different approach to the same problem. Its mainspring is limited to the more even part of its range by a stop-work mechanism, and a declutch lets the automatic rotor keep winding once that limit is reached. A barrel that turns during winding drives the going train through the arbor, and a small indicator shows the remaining reserve. The aim is steadier power delivery to the regulating system, not a longer reserve.

Both watches share a visible design principle: the working parts are the decoration. That is an appealing idea for an owner who wants to study the watch, and it also means that a service will expose the mechanism at close range, so the shop should be comfortable working on what the watch is designed to show.

Armin Strom's published owner's guides recommend maintenance every three to five years, carried out by the brand or an authorized retailer. The terms warn that unauthorized warranty work can invalidate a claim, so for a watch still under warranty, the brand's service route is the safest option. Contact the Biel concierge before sending a watch, and ask for the estimate, the shipping arrangements and the expected timing in writing.

Out of warranty, an independent can be a reasonable choice if it has worked on dual-regulator movements or skeleton calibers before. Ask how it will handle the regulating system, whether it has the tools and experience to reset the coupling and check synchronized running, and how it sources parts for a reference from a relatively young caliber line. A shop that can't explain its plan for the parts should not be the one to open a Resonance.

Ask for a quote that covers the movement, the case and any water-resistance work separately. The owner's guides also suggest that water-resistance testing takes place every two years, and whenever the case is opened, so a service should include a test at the end and a record of the result.

An open dial or skeletonized movement exposes more of the mechanism to dust, oil migration and handling. A good watchmaker will protect the exposed parts during service and will clean the movement with a method it can explain. Ask whether the shop uses a cleaning process that is safe for the lubricants on the regulating system, and whether it will return any part it replaces.

The regulating system deserves particular care. On a Mirrored Force Resonance, the two balances and their clutch spring need to be checked together, not one at a time, because the coupling affects how the watch runs. Ask the watchmaker how the synchronized running is checked after reassembly, and whether the result will be recorded or shown to you.

Wear on the case and crystal is less visible on an open dial, but the seals are just as important. Replace them at each service, and ask for the water-resistance test to be recorded on the paperwork you receive back.

For a pre-owned watch, the papers come first. The warranty card should be dated, stamped and signed as the brand requires, and the reference and serial number should match the watch. Armin Strom has released limited editions and first editions, and some first editions carry an extended warranty, so check the documents for the edition you are considering rather than assuming the standard five-year term applies.

Look at the mechanism. On a Resonance, both seconds displays should run, and the pusher should reset them together. On a Gravity Equal Force, the remaining reserve indicator should move in a way that matches the watch's running, and the rotor should wind the watch without a rough or irregular feel. Ask for a service record, and ask whether the case has been opened by anyone other than the brand or an authorized center.

Choose a specialist who can explain the reference's caliber and parts, who will show you the synchronized running or reserve indicator after work, and who gives a written estimate. The best sign is a shop that asks questions about the watch before it quotes.