In Depth – The Rolex Zenith Daytona Cosmograph

by Ross Povey - Apr 12 2019
In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons

Rolex aren’t known for their giant leaps in model development. Each year as we eagerly await the latest releases at the spring Baselworld fair, we generally see small incremental steps in model variations. Admittedly we sometimes see a left-field curve ball  – remember the year the first Rainbow Daytona was released? Love it or loathe it nobody can argue with the technical elements of the gem setting or the huge impact it’s had on the sports watch market. This wasn’t the first time, however, that Rolex took the watch world by surprise and unveiled a Daytona that would be the one of the most sought after watches on the planet. In 1988 Rolex shared a watch that would shape the brand’s future and create a whole collectors’ niche like nobody had seen before. The Rolex Zenith Daytona reference 16520 was literally a game-changer.

In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons
In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons
A nice black dial with mellow patina on the rings in the sub dials – a common trait on black dial 16520s

Radical Redesign

We are passionate about design and aesthetics here at Bulang and Sons – its what inspires us to do what we do. If asked the question about who the most important watch designer of the 20th century was, a lot of people would probably say Gerald Genta. Why? Well, arguably he’s the most famous as his work transcends the brands he designed for. Watch design doesn’t happen by accident and it takes as long as five years to take a watch from initial sketches, through prototypes to the final version. Rolex’s redesign of the Daytona was huge. Not just a huge amount of design changes but the impact that it had was huge. So, we raise our glasses to the designer who was tasked with the Daytona facelift!

The first series of Daytonas had never been popular watches and would often languish in authorized dealers’ shops for years. Maybe it was because it was small at 37mm with 19mm lugs or possibly the manual winding movement put people off. It wasn’t unheard of for dealers to use them as ‘sweeteners’ when trying to sell more expensive gold watches. Imagine that conversation – “Well, if Sir was to take the yellow gold Day Date today, we would be happy to include this steel 6239 and if you don’t like the exotic dial we can add a regular silver or black dial to Sir’s liking”. But in 1988 the Daytona went from lame duck to serene swan.

In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons
The Rolex 6263 Oyster Cosmograph Daytona, today one of the most iconic watches. Back in its days not so popular.

Sapphire Era

A non-porcelain Mk1 ‘floating’ Daytona 16520 ((pic: Only Vintage by Corrado Mattarelli/Luca Garbati)

The most instantly noticeable aspect of the new 16520 Daytona was the case. The two big changes were the size, which had been increased to 40mm and the introduction of crown guards on either side of the winding crown (a 700-series trip-lock winding crown). This was a significant design element and enabled the Daytona to stand side by side, proportionally, with the Submariner and GMT-Master. The domed acrylic crystal was replaced with a flat sapphire glass, which whilst making the watch much more hardwearing also gave the watch a lower profile on the wrist.

The very first porcelain Mk1 dial with so-called ‘floating’ COSMOGRAPH text – known as the Floating Daytona (pic: Luca Garbati)
You can really see the 3D effect on the porcelain dial from this angle (pic: VWC by Jatucka/Luca Garbati)
In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons
Low profile sapphire was a big change to the previous domed acrylic glass
In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons

Rolex kept the steel tachymeter bezel as standard, removing the option of a black bezel. It wasn’t until the introduction of the reference 116500 at Basel in 2016 that a black bezel would return to a steel Daytona. The new case had 20mm lugs, which meant that Rolex could utilise their sports bracelets on the watch, which they did on the early 16520s by fitting the solid link Oyster bracelet reference 78360. This was fitted for the first few years until, in 1993, Rolex began fitting Oyster bracelet reference 78390 with short flip-flock clasp and polished centre links.

In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons
In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons
A new-era classic
In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons
The rare Mk2 with four lines of text and early ‘200’ bezel, with the UNITS PER HOUR text at 9 o’clock

Perpetual Spirit

The modified Zenith El-Primero movement calibre 4030 (pic: Cattin Collection/Luca Garbati)

The biggest development for the Daytona at the 1988 launch was the automatic movement. The movement was based on the Zenith El-Primero calibre 400, which is why collectors refer to these watches as Zenith Daytonas. Of course, Rolex didn’t simply drop a Zenith movement into their watches – the base calibre went through more than 200 modifications before Rolex were happy to sign off on it and give it their own reference number – the calibre 4030.  Changes were made to the balance bridge, with the addition of Rolex’s Micro-Stella adjustment system, as well as the shock-proofing system. The rotor, lower plate and escapement wheel were replaced entirely and ultimately Rolex were able to increase the power reserve of the watch from 42 to 52 hours – that’s a significant increase! The finished 4030 movement was then submitted for COSC testing which it passed and then enabled Rolex to adorn the dial with the SUPERLATIVE CHRONOMETER OFFICIALLY CERTIFIED text. 

SCOC – Chronometer rated 16520 (pic: VWC by JATUCKA/Luca Garbati)

A Weighty Wait

A reimagined aesthetic and significant developments in calibre technology meant that Rolex were presenting something special in 1988. Taking all that into account and not diminishing the importance of this – simply put, they made the watch better and cooler than it had ever been in the eyes of the watch buying public. This isn’t in any way to say that the plexi Daytona isn’t incredible and beautiful and one of the most important watches for vintage collectors. We are discussing the context of the general public watch buying community in the late 1980s. And they went for it…big time!

In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons
Dressed down – the black 16520 on a black nylon nato. You can find some cool Nato Straps here

If you have more than a passing interest in watches you will be familiar with the waiting lists imposed on Rolex dealers due to the staggering demand for steel sports watches versus the actual supply that Rolex delivers. The new Pepsi-GMT, the ‘Hulk’ ceramic bezel Submariner Date and the ceramic bezel Daytona have months and years-long waiting lists. This has a knock-on effect on the grey market where these watches can sell with markups in excess of 70 percent. The steel Daytona started this trend with Rolex timepieces and specifically the reference 16520 in 1988. Everybody wanted one and it was a watch with a price point that was accessible to buyers. And why wouldn’t it be? It is an amazing watch that truly addressed the market’s concerns. It was Rolex listening to dealers and customers, taking the feedback on-board and delivering the perfect response.

In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons
The 18kt yellow gold 16528 Daytona

The Small Things

Collectors love the details in watches. It could be argued that collecting only exists because people enjoy amassing examples that are identifiable by small differences, most of which would be lost on the casual observer. The 16520 Daytona was one of the last lines of watches where Rolex made changes to the watch over the duration of its life-span to improve and tweak the watch. Most of these changes occurred on the dials and the bezel and has resulted in an identified chronology and so-called ‘Mks’ in the dial versions. Traditionally there were five Mks in the steel Zenith Daytonas, although now it is accepted that there are nine different versions – Mk1 to Mk9.

In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons
Zoom in – its all about the details

We will document and discuss these variations in a later article, but its important to remember that it is these small changes that make the watches so collectible. Rolex now has a very rigorous quality control system, whereby watches produced are consistent and we no longer really see such a range of variations. The successor to the steel 16520 was the in-house movement 116520 – this watch has a couple of variations that collectors have picked up on, but nothing like the Zenith-era pieces. And that’s what collectors love and hunt for. Recent posts on Instagram have highlight that the first batch of the new Pepsi ceramic bezel GMT-Masters have a slightly different colour ceramic to more recent watches. This isn’t fading, as Cerachrom (Rolex’s propriety ceramic compound) doesn’t change colour – therefore it’s a production variation. So collectors have now identified Mk1 and Mk2 version of the watch. Its small, but its important and that’s what makes collecting what it is.

Rolex also introduced the Daytona in precious metals on a leather strap, with small fixed endlinks. This model in 18kt yellow gold 16518 with white dial and brilliant set hour markers
(pic: Cattin Collection/Luca Garbati)
The 18kt white gold on leather was given the reference 16519. A new arabic numeral dial was also introduced alongside a new bezel font.(pic: Cattin Collection/Luca Garbati)
The new bezel for precious metal Daytonas (pic: Cattin Collection/Luca Garbati)

Easy Wearer

The combination of the sapphire glass and the proportions of the case make the 16520 a great watch to wear. Prices of Daytonas only ever go one way and no more has this been seen than with the Zenith watches. Prices have literally tripled over the past couple of years. Some of this is the back draft from the insane prices now for plexi-Daytonas for collectors and also the market trend for the current models, including the ceramic bezel steel watch and the ever-in-demand Rainbows. Daytona collecting is its own genre, almost separate from Rolex collecting, led by the Italians who have always seen it as a key watch.

Bulang and Sons Rolex Zenith Daytona 16520 Watch Strap
Style it up – the Bulang and Sons Suede Straps you can find here
Bulang and Sons Rolex Zenith Daytona 16520 Watch Strap
Classy Style with the Cognac Suede Leather Strap

To us the 16520 is a watch that is an important part of the Rolex story. It isn’t really a vintage watch yet, but more of a transitional model from an era when Rolex began adopting modern watchmaking methods and materials into their watches. In these times, wearing a 6263 or 6239 plexi glass Daytona is getting more and more risky for daily wear as prices force owners to keep the watches in the safe and wear them for high days and holidays. The 16520 is perfect for a daily wearer and is versatile enough to be worn on different straps when a change is needed. That’s why we love it!

In Depth – The Rolex Zenith Daytona Chronograph ref. 16520 at Bulang and Sons
Thin, sporty and elegant… the Cavallo Faded Brown Shell Cordovan Strap you can find here


Rolex Perpetual Cosmograph Daytona Strap Guide


Bulang and Sons Rolex Zenith Daytona 16520 Watch Strap

Bulang and Sons Rolex Zenith Daytona 16520 Watch Strap
Try them on a Deluxe Nylon Nato for some Tool Watch look
Bulang and Sons shop