Audemars Piguet Royal Oak RD#5: an anniversary manifesto

After months of speculation, the Swiss manufacturer from Le Brassus concluded its 150th anniversary celebrations (1875–2025)
with a premiere that market analysts consider more than just an anniversary gadget. The Royal Oak ‘Jumbo’ Extra-Thin Selfwinding Flying Tourbillon Chronograph RD#5 is the engineering culmination of a decade of watchmaking research and experimentation.

When Audemars Piguet celebrated its 150th anniversary in 2025, collectors and investors expected fireworks. However, the brand, currently headed by Ilaria Resta, chose a path of visual restraint combined with technical bravado. Unveiled in October 2025, the RD#5 (ref. 26545XT) is not a baroque display of wealth, but a cool, engineering calculation of millimetres and the laws of physics. As Tracey Llewellyn of Britain’s Revolution Watch noted, the launch ‘seems less a commemoration and more a manifesto’ to define the direction of precision mechanics for decades to come [1].

Return to ‘Jumbo’

The key to understanding the new model is its case. In the world of luxury sports watches, the term ‘Jumbo’ refers to the historic 39 mm size defined by Gerald Genta in 1972. Over the years, complications (additional functions of the mechanism) have forced watches to increase in diameter and thickness, often ruining their ergonomics.

The RD#5 breaks this deadlock. Engineers have managed to enclose two of the most prestigious and space-consuming complications – a flying tourbillon and a flyback chronograph – in a case with a diameter of 39 mm and a thickness of only 8.1 mm. As noted by SJX Watches, this is identical to the dimensions of the RD#3 (tourbillon without stopwatch), an unprecedented achievement in miniaturisation. Mark Kauzlarich of Hodinkee described this result as ‘a return to the most wearable watch on the market,’ emphasising that this time, technical advancement did not come at the expense of user comfort [3].

Anatomy of the Calibre 8100 and new materials

At the heart of the RD#5 is a new movement marked with the symbol 8100. Unlike standard modular designs, where additional layers of functions are added to the basic movement, the Calibre 8100 was designed as an integrated whole, which made it possible to maintain a record-breaking flat profile.

An equally important innovation can be found in the materials used. Audemars Piguet did not limit itself to titanium. According to industry sources, the design combines it with elements made of bulk metallic glass (BMG) [2]. This is an amorphous alloy with exceptional hardness and scratch resistance, giving the bezel a characteristic shine, contrasting with the matte finish of the rest of the case.

It is worth noting that the watch face, made in the brand’s characteristic blue Tapisserie pattern, serves a masking function in this model. Instead of displaying every mode, AP has opted for discretion. The only clues to the complexity of the mechanism are the tourbillon cage at six o’clock and the subtle placement of the chronograph counters.

The End of the RD Era?

According to official brand announcements, the RD#5 model marks the final chapter in the Research & Development saga.
It crowns a series of intricate creations and bold horological experiments, including:

– the RD#1 model, presented as the Royal Oak Concept Supersonnerie, which revolutionised the acoustics of striking watches; thanks to a case that acts as a string instrument, the clarity and volume of the sound were unprecedented in water-resistant wristwatches;

– the 2018 RD#2 model, which set a new standard for thin perpetual calendars: its three-layer architecture, enclosed in a single plane, housed a complex movement in a case only 6.3 mm thick;

– the RD#3, introduced in 2022, a triumph of miniaturisation: watchmakers managed to fit a newly developed self-winding flying tourbillon into an ultra-thin ‘Jumbo’ case (8.1 mm), while maintaining its historical proportions;

– the RD#4 model, known as Universelle and housed in a Code 11.59 case: in 2023, this movement became the manufacture’s magnum opus, integrating over 1,100 components supporting as many as 23 complications (including Grande Sonnerie and perpetual calendar) in an exceptionally ergonomic and easy-to-use format.

Currently, the RD#5 combines the experience gained with the RD#3 and RD#4, applying it to chronographs. This is a clear signal to the market: the period of laboratory testing is over, and the technologies developed will now gradually enter series production, although the RD#5 itself has been limited to only 150 pieces [4].

Market Context

The decision to limit production to 150 pieces renders the RD#5 almost theoretical from the perspective of the average buyer. However, for luxury market analysts, the signal that Audemars Piguet is sending to its competitors – especially Patek Philippe and Vacheron Constantin – is more important. In its anniversary year, the company did not delve into its archives to create
a simple vintage reissue, but invested in a new calibre.

Ilaria Resta, CEO of AP, emphasised ‘innovation as tradition’ in her anniversary statements. In the case of the RD#5, this is borne out by the facts. This watch is proof that even in the saturated market of so-called integrated bracelet sports watches, the masters of the craft still have something to compete for.

Verdict

The Audemars Piguet Royal Oak RD#5 is not a watch for everyone, not only because of its prohibitive price and limited availability. It is a cool, technical instrument. For purists, titanium may seem too light, and the combination of a tourbillon and
a chronograph unnecessary. However, as the culmination of 150 years of brand history, this model fulfils its purpose: it proves that the ‘Jumbo’ can still be a platform for innovation, not just a nostalgic reminder of the 1970s.

Sources:

1. Llewellyn, T. (2025). Audemars Piguet Concludes RD Series With Royal Oak ‘Jumbo’ Extra-Thin Flying Tourbillon Chronograph RD#5. Revolution Watch.
2. SJX (2025). Audemars Piguet Royal Oak RD#5 with Palladium BMG Case. SJX Watches.
3. Kauzlarich, M. (2025). Hands-On: Audemars Piguet Royal Oak RD#5. Hodinkee.
4. Audemars Piguet Official Website (2025). Royal Oak RD#5 Technical Specifications.

Photos: audemarspiguet.com