A Third Way to Regulate: How Omega’s Spirate System Reinvented Mechanical Watch Accuracy

For roughly 250 years, every watchmaker on earth regulated a mechanical movement in one of two ways. Either you moved index pins along the hairspring to change its active length, or you shifted tiny weights on the balance wheel to alter its moment of inertia. Both methods worked. Both carried trade-offs. And both remained fundamentally unchanged since Abraham-Louis Breguet was refining overcoil springs in the 18th century.

In January 2023, Omega introduced a third option. It was not a refinement of index pins, and not a variation on free-sprung balance wheels. Instead, the Spirate System adjusts something neither of the traditional methods touch: the stiffness of the hairspring itself. By 2026, the system has expanded from a single chronograph caliber into a new Constellation collection, where it enabled a milestone that seemed almost paradoxical. A two-hand watch, certified as a Master Chronometer, with no seconds hand to verify it.

Two Methods, Two Centuries

Index-pin regulation is the older and more common approach. A pair of pins straddles the outermost coil of the hairspring, and a lever slides them along its length. Move the pins inward, shortening the active portion of the spring, and the balance oscillates faster. Slide them outward, lengthening it, and the balance slows. Most Swiss movements sold today still use this method because it is simple, intuitive, and easy to teach. A competent watchmaker can bring a movement within COSC tolerances in a few minutes.

But index pins have a structural weakness: they grip the hairspring between two points, and any play between pin and spring introduces positional error. When the watch changes orientation on your wrist, the hairspring shifts fractionally between the pins, altering the rate. Gravity becomes noise in the system.

Free-sprung regulation eliminates the pins entirely. Instead of constraining the spring, it redistributes mass on the balance wheel. Rolex’s Microstella system uses four gold screws threaded through the balance rim. Turn a screw inward, concentrating mass closer to the center, and the wheel accelerates, like a figure skater pulling their arms tight. Turn it outward and the wheel slows. Patek Philippe’s Gyromax system uses a similar principle with weighted tabs that rotate in or out of recesses on the balance rim.

Free-sprung movements generally perform better across positions because nothing touches the hairspring. But calibrating them requires extraordinary precision. Moving a Microstella screw by a fraction of a millimeter can swing the rate by several seconds per day. And the adjustment itself demands removing the balance from the movement, working under magnification with specialized tools, then reinstalling and testing. If a tool slips and nicks the hairspring, the entire balance assembly is ruined.

A Blade on a Spring

Omega’s Spirate System does not adjust the length of the hairspring or the weight distribution of the balance wheel. It adjusts the spring’s stiffness by adding a controlled, variable tension to it through a flexible blade.

Physically, the blade is a thin strip of silicon that attaches to the outer coil of Omega’s Si14 hairspring. From that attachment point, a long curved “tail” extends outward, arcing across the movement to connect to the balance bridge. Because both the blade and the hairspring are manufactured from the same silicon wafer using deep reactive-ion etching (DRIE), they form a single monolithic structure. No adhesive, no mechanical fastener, no separate part to work loose over time.

At the balance bridge, two adjustment points govern how much tension the blade applies to the hairspring. A regulating arm, engraved with plus and minus symbols, provides coarse adjustment by repositioning where the tail anchors. Below it, a snail cam engraved “0.1 s/d” allows micro-adjustments of one-tenth of a second per day. When a watchmaker rotates the cam, the tail’s attachment point shifts slightly, pushing or pulling on the flexible blade. Pushing increases tension, stiffening the hairspring, which makes the balance oscillate faster and the watch gain time. Pulling decreases tension, softening the spring, slowing the beat.

Travis Hines, head watchmaker at Hodinkee, described the principle in clear terms: “Omega has essentially created a third type of regulating system where instead of changing the weight on the balance or using index pins, they’re actually adjusting the stiffness of the balance spring itself. So as the spring gets stiffer, it’s going to cause the balance to run faster and as it loosens up, it’ll run slower.”

Why Stiffness Matters More Than Length

Adjusting the stiffness of a spring is not the same as adjusting its length, and the distinction has practical consequences. When index pins shorten a hairspring, they also change the spring’s geometry in ways that are difficult to predict precisely. Shortening by one coil versus one-and-a-half coils does not produce a proportional change in rate because the inner and outer coils of a spiral spring contribute unevenly to the overall restoring force. Fine adjustments with index pins are possible but inherently nonlinear.

Stiffness adjustment, by contrast, acts uniformly across the entire spring. Adding tension to the blade increases the effective spring constant without altering the hairspring’s geometry or active length. Every coil still participates in the oscillation. And because the snail cam translates rotational motion into tiny linear displacements along the tail, the relationship between cam position and rate change is much closer to linear. One click of the cam equals a predictable, repeatable increment. Omega’s claim of 0.1 seconds per day per increment is not marketing language; it reflects the mechanical precision of the cam’s geometry.

Hines emphasized the downstream benefits for serviceability. With free-sprung regulation, adjusting the rate means working directly on the balance wheel with heavy tools near a fragile silicon hairspring. One accidental contact destroys the spring and requires replacing the entire balance assembly. With Spirate, the adjustment points sit on the balance bridge, physically separated from the hairspring. “I think this is actually significantly better for the boutiques now, with these regulating points away from anything that you could accidentally hit,” Hines said.

Manufacturing the Monolith

Silicon hairsprings are manufactured using a photolithographic process borrowed from the semiconductor industry. A silicon wafer is coated with photoresist, exposed to UV light through a mask defining the spiral pattern, and then etched using DRIE to cut through the wafer. Hundreds of identical hairsprings emerge from a single wafer, each one dimensionally identical to the others within tolerances measured in microns.

Omega’s innovation with Spirate was to include the flexible blade and its tail in the same mask design. Rather than manufacturing the blade separately and bonding it to the hairspring afterward, both components are etched from the same piece of silicon in a single step. Monolithic construction eliminates the interface between two bonded parts, where stress concentrations, thermal expansion mismatches, and fatigue failures tend to originate. It also means that every Spirate hairspring produced on a given wafer has the same blade geometry, the same tail curvature, and the same relationship between applied tension and stiffness change.

This consistency is what allows Omega to promise industrialization. A hand-fitted component with unique tuning characteristics would not scale. A photolithographically defined component, produced in batches of hundreds, scales the same way microchips do.

From Super Racing to Constellation Observatory

Omega debuted the Spirate System in the Speedmaster Super Racing, powered by Caliber 9920, a column-wheel chronograph rated to 0/+2 seconds per day and certified by METAS as a Master Chronometer. At launch, it was the only Omega movement to carry the system, and the watch itself was positioned as a showcase for the technology rather than a mass-market product.

By 2026, the system had migrated into something unexpected: the Constellation Observatory, a collection of two-hand dress watches with no seconds hand, no chronograph, and no obvious connection to the Super Racing’s motorsport identity. What it carried instead was a new pair of calibers, the 8914 and 8915, built on Omega’s established 89xx architecture but fitted with the Spirate System and a skeletonized rotor bearing the Constellation’s Observatory medallion.

Certifying a two-hand watch as a Master Chronometer presented a logistical problem. METAS testing traditionally requires observing the seconds hand to measure rate. Without one, Omega and METAS developed an acoustic testing method. Microphones listen to the tick of the escapement, and software measures the interval between beats with the same precision that optical timing machines achieve by watching a seconds hand sweep. It is a small procedural change with a larger implication: accuracy certification is no longer tied to the presence of a seconds display.

What Competitors Face

Omega’s Spirate System sits within a broader context of tightening accuracy standards across the Swiss industry. Rolex’s Superlative Chronometer certification promises +/−2 seconds per day. COSC recently announced its Excellence Chronometer standard, raising the bar above its traditional −4/+6 tolerances. Omega’s 0/+2 specification, achieved through Spirate, is asymmetric by design: the watch can gain up to two seconds but cannot lose any. In practice, a watchmaker adjusts the Spirate cam to place the rate just above zero, and the system’s precision prevents it from drifting below.

Hines placed the significance of Spirate in historical context. “I would put this almost on par with moving away from the traditional blue steel hairspring to using a Nivarox alloy,” he said, referring to a transition in the early 20th century that represented a generational leap in accuracy and magnetism resistance. “I’d consider this to be a bigger jump than Omega’s 2008 move from Nivarox alloy hairsprings to silicon hairsprings because this is an entirely new regulating principle.”

Any brand competing on accuracy now faces a specific question: can they replicate a third regulation method, or must they refine the two that already exist? Rolex and Zenith, both companies with deep investment in free-sprung regulation and silicon hairspring manufacturing, have the technical infrastructure to explore similar approaches. Whether they pursue stiffness-based regulation or develop something else entirely remains open. What has changed is that two options are no longer enough to define the frontier.

What Buyers Should Know

For watch buyers evaluating Spirate-equipped models, three practical details matter. First, the 0/+2 seconds per day rating is a certified specification, not a marketing target. Every Spirate-equipped watch passes METAS testing on the wrist, not just on a test bench as a bare movement. Second, regulation adjustments at authorized boutiques become simpler and lower-risk. Because the snail cam sits away from the hairspring, a service technician can fine-tune rate without disassembling the balance, reducing both the time and the probability of accidental damage during routine service. Third, the monolithic silicon construction means the Spirate blade shares the hairspring’s anti-magnetic properties. Silicon is inherently diamagnetic and unaffected by magnetic fields up to 15,000 gauss, the threshold Omega tests to for Master Chronometer certification. Adding the blade does not introduce a new magnetic vulnerability.

In a market where most mechanical watches are accurate to within five or ten seconds per day, shaving that margin to two seconds may seem incremental. But for Omega, the point was never the two seconds. It was proving that the fundamental physics of regulation had a third solution no one had built before.