Learn about Audemars Piguet Royal Oak double balance wheel hollow

Audemars Piguet copy took the lead in solving one of the oldest problems in the watchmaking industry: the double balance wheel inside the Royal Oak skeleton

The balance wheel is often regarded as the heart of a mechanical watch. The balance swings back and forth because it is connected to the hairspring, which is a slightly elastic flat metal spiral. Most balance springs are fixed at the center and outer poles of the spiral. Due to the two fixed endpoints, they cannot breathe concentrically. When the watch is placed vertically and gravity acts on the balance spring, the problem becomes more serious, making the balance spring eccentric.

One solution is to use two stacked balance springs, each of which mirrors each other and average out any errors. Laurent Ferrier and H. Moser & Cie. Both have double hairsprings installed on the watches (by the way, they all use the same hairspring made by Moser’s sister company Precision Engineering), and Montblanc even uses double cylindrical hairsprings, one inside the other.

Audemars Piguet went a step further and launched the Royal Oak Double Balance Skeleton exact replica watches at SIHH in 2016. The watch is equipped with two superimposed balance wheels, each with its own balance spring.

In addition to the advantages of dual hairsprings, the two balance wheels also mean that the inertia of the regulator is doubled, which ensures a more stable timekeeping, because the body with greater inertia is more likely to continue to move without being affected by vibration.

However, the downside is that moving the second balance requires additional energy-the power reserve of the dual balance is reduced by 45 hours, while the movement of the single balance is reduced by 60 hours. All in all (no pun intended), the pros and cons outweigh the pros and cons, which is why this cheapest replica watches has been put on the market.

Except for the regulator, the rest of the movement 3132 is functionally the same as the automatic movement 3120 inside Audemars Piguet. It is decorated as a skeleton bridge, revealing the mechanical principle of the movement. In fact, this movement is almost the same as the movement of the Royal Oak Skull. 15305 except for an obvious gift: a red gold bridge with double balance wheels.

The movement is a typical Audemars Piguet movement, using a hollow process, hollowed out in a modern style, and uses smooth lines and geometric shapes. All the movement decorations are neat and clean, with obvious polished bevels on many of the edges of the bridge. These surfaces are obviously diamond cut, resulting in distinctive and shiny edges, with one exception. The golden bridge of the balance seems to have hand-finished edges, causing slight unevenness.

All bridges are plated with ruthenium to form a dark gray coating, which means that the eyes will be immediately attracted by the brighter rose gold-plated parts of the dial, namely the hands and balance bridge.

The rest of the watch is a vintage Royal Oak, with a beautiful case, mirror-polished edges and a brushed flat surface. Royal Oak is one of the few reasonably priced watch cases, even in the stainless steel case, it looks and feels so expensive.

The Royal Oak Double Balance Wheel Openworked has a diameter of 41 mm and a height of 9.9 mm. The second balance wheel needs extra height, which means it is slightly thicker than the framed Royal Oak, and the single balance wheel has a height of 9.4mm. Although the watch is not big, it looks chunky and horny on the wrist.

Rose gold openwork Royal Oak double balance wheel (ref. 15407OR.OO.1220OR.01), stainless steel version (ref. 15407ST.OO.1220ST.01).