Audemars Piguet Royal Oak Perpetual Calendar Ultra-Thin 26586IP.OO.1240IP.01
A few minutes into this review, you might be wondering if its been given the wrong title. You came here for the AP Perpetual Calendar Ultra-Thin, and yet someone is waffling about Jaeger LeCoultre and the fella behind the concept of gravity.
Sounds weird, but you’re not in the wrong place.
Isaac Newton once said “If I have seen further, it is by standing on the shoulders of giants”
In a nutshell - progress is made by building on the work of those who have gone before us.
In this case, the giant is Jaeger LeCoultre’s venerable Calibre 920.
First introduced in 1967, it is a both a work of art and a technical tour de force.
It’s a 36 jewel ultra thin automatic movement with a free sprung Gyromax balance and powered by a full sized bi-directional rotor which runs on a beryllium rail for stability.
In short, it’s an absolute peach.
It is elegant, robust, beautifully laid out, stable, and ultra reliable.
It pre-dates the moon landings.
It is also, probably surprisingly The Godfather of the Royal Oak and the Nautilus. Without the 920, these watches may not have existed, let alone been as searingly popular as they are today.
The original Genta Royal Oak 5402ST and the Nautilus 3700 from 1972 and 76 respectively were both powered by the base Calibre 920.
Without it, AP and Patek wouldn’t have been able to pull off the wide case and slim profile proportions that made these watches into legends.
Fascinatingly, the 920 was never used inside any of JLC’s watches. It was sold as a movement kit (or to use the technical term, an Ebauche), and was only ever made available to the Holy Trinity of Audemars Piguet, Vacheron Constantin, and Patek Philippe.
Once the big three had it in their hands, they were free to decorate, tinker, build upon and personalise it to their hearts content.
The ebauche is so important, that when JLC was being sold to the Richemont group in 2000, AP as 40% stakeholders successfully negotiated rights to continue its use.
As an aside, given that Audemars have full manufacture rights over the 920 and have modified it so significantly at times, it is absolutely an in-house movement.
So, which current powerhouse has a highly modified 920 powering its heart?
The Audemars Piguet Royal Oak Perpetual Calendar Ultra-Thin.
See? We got here in the end.
AP is no stranger to perpetual calendars. They made the worlds first perpetual calendar wristwatch in 1955.
In 2018, some 63 years later having well and truly mastered the art, AP released a full platinum Royal Oak Perpetual Calendar Ultra-Thin concept piece, the RD2.
RD stands for research and development, 2 being the second watch to be presented by the R&D department (the first was a minute repeater)
The RD2 was crowned GPHG’s (Grand Prix D’Horlogerie De Geneve) watch of the year, and with VERY good reason.
It was, at the time, the worlds thinnest Perpetual Calendar, or “Quantieme Perpetuel” as AP calls it and measured an insane 6.3mm thick.
This record was beaten in 2021 by Bvlgari and their Octo Finissimo Perpetual Calendar which comes in at 5.8mm thick.
That said, the AP has an additional moon-phase complication and uses a full sized rotor while Bvlgari went with a a micro-rotor system.
The RD2 achieved a staggering ultra thin perpetual calendar movement by mounting the parts required for the calendar across the modified 920 base calibre in a single plane design rather than stacking.
This created a “one layer” mechanism for the entire piece rather than one layer for each specific calendar function.
The rear of the dial is used as a movement bridge to hold the calendar components so no space is lost or wasted in the pursuit of thinness.
The result of this development was the 2.89mm thick AP calibre 5133.
In 2020 AP launched the commercially available but ultra limited variant of the RD2, the 26586IP which instead of being full platinum is made from grade 5 titanium with a platinum bezel (secured by white gold bolts), middle links and clasp logo.
If its polished on this watch - it’s platinum.
There was also a change to the dial which has gone from the tapisserie of the RD2 to a a metallic blue with vertical graining.
Im not sure of the thinking behind the change, but the flatter blue certainly makes things look less busy, which on a dial bursting with so much information can only be a good thing.
The real estate of the dial is as follows:
Photo-realistic moon phase at 12
Month at 3
Leap year just below
Date at 6
Day at 9 with day/night indicator tucked beneath it.
Being a perpetual calendar which takes account of leap years and everything else besides, once set you wont need to change any settings (which are taken care of by inset push buttons) until the year 2100.
Perhaps keep the instructions somewhere safe for the grandkids or the martians depending on how things pan out.
Wear-wise, this is a 41mm but wears visually larger as its thinness creates an optical illusion of the watch being broader than it really is.
The overall length at 53mm across the wrist also lends itself to looking on the bigger side. In real world conditions, it wears closer to a 42 or 43mm piece. But, as my preference is for a bit of presence, I’m happy with that.
Water resistance is 20mm so splash proof at best.
This is a trade off between the complexity of the watch and its push setting system and robust water-proofing and it’s fair enough.
I’m going to hazard a guess that those with this particular AP on their wrist may have a couple of other watches here and there that would be more suited to riskier pursuits.
This is quite possibly the Royal Oak to end all others.
Looking objectively at one of the holy trinity of watchmakers finest pieces, this is
an award winner, a feat of history, research, development, hours of design and painstaking labour, beautiful finishing, blood sweat and tears, and selecting one thing that I, a comparative nobody, would change for the sake of a balanced review -
The bezel gets fingerprint smudges like you wouldn’t believe.