Audemars Piguet Royal Oak RD#2, The World’s Thinnest Self-Winding Perpetual Calendar (SIHH 2018)

As with all industries, the watchmaking world is subject to trends. One that we’re not unhappy to see resurfacing is ultra-thin watches. Piaget kicked things off in December with the thinnest automatic watch, followed at the SIHH 2018 by the thinnest mechanical watch ever created (2mm thick, no less). It is now time for Audemars Piguet to come on board and demonstrate, if it’s even necessary, that they know a bit about watchmaking. Here is the Royal Oak RD#2, which at a staggering 6.30mm thick is the thinnest self-winding perpetual calendar on the market today.

Reminder 1… Audemars Piguet has always had a soft spot for ultra-thin watches. Forget about the massive Royal Oak Offshore Tourbillon/Grande Complication/Diver Chronograph. Instead, take a look at the watch that created the modern side of Audemars, the 1972 Royal Oak 5402ST. It was and still is one very thin watch, with an automatic movement that was thinner than most hand-wound calibres. Its modern iteration, the 15202, follows the same idea, with its movement measuring only 3.05mm thick and its case 8.1mm (which is quite impressive, knowing the specific construction of this case).

Reminder 2… How are most perpetual calendar watches constructed? Basically, with the exception of a few pieces, most QP’s are built in a modular way. That means that watchmakers add a module on top of an existing movement. Not the best solution to shaving millimetres. If you consider a movement with self-winding capacity, it means a 3-layer architecture – QP module/movement/rotor. Really not the best for thinness.

Let’s get back on today’s topic, the new Audemars Piguet Royal Oak RD#2 Perpetual Calendar Ultra-Thin 26586PT. A few specifications:

• Overall thickness of the case: 6.30mm
• Overall thickness of the movement (perpetual calendar and self-winding capacity included): 2.89mm

So, if you consider what we said above concerning the time-and-date Royal Oak Extra-Thin (8.10mm case and 3.05mm movement), it means that by adding a perpetual calendar function to this watch, Audemars Piguet has succeeded in shaving almost 2mm off the case and in making a far more complex movement thinner than its simple time-and-date version. Quite impressive!

At the time of writing this article (prior to the SIHH 2018), we don’t have yet all the details concerning this Royal Oak RD#2 Perpetual Calendar. As often with its research and development (RD#) watches, Audemars Piguet keeps a bit of secrecy around its technical prowess. We’ll definitely benefit from the show to ask more questions about this watch and we’ll come back with a technical article soon, the MONOCHROME way.

What do we know now? The basic principle to achieve such thinness is to work on both the architecture of the movement and on the architecture of the case – and, indeed, Audemars did both for this Royal Oak RD#2.

First, the classical 3-layer construction of the movement has been re-engineered to become a whole. Based on the same architecture as the Calibre 2121 used on the 15202ST, it has taken five years to develop the new ultra-thin calibre 5133 with perpetual calendar, which now uses a single-level architecture. It means that all the parts of the perpetual calendar (the grand levier, the programmed wheel, the gears and springs used to actuate the multiple indications) are not built as a module added on top of the movement but are fully integrated into the base of the movement, allowing for the shaving off of a few millimetres. Same goes for the self-winding module.

The same idea has been applied to the case and to the display. While visually familiar, the new 950 platinum case (with a 41mm diameter and a 6.30mm height) has been slightly redesigned to allow for extra-thinness. On the dial side, we can see that all the indications are on only 2 levels – one level for the QP indications, with none of them overlapping and a second level for the hours and minutes. Despite this incredible thinness, all the indications of a traditional perpetual calendar are present, including a moon-phase at 12 and the leap-year.

In terms of design, this Audemars Piguet Royal Oak RD#2 Perpetual Calendar Ultra-Thin 26586PT makes no surprises, with a blue dial adorned with “Grande Tapisserie” guilloche pattern and the integrated chain-like bracelet. A concept watch in terms of mechanics, yet faithful to the origins of the model design-wise.

More details to come during/after the SIHH 2018. No price or availability announced yet, as this watch is for the moment a concept. www.audemarspiguet.com.