6 minutes

El Primero: How Zenith Helped the Rolex Daytona Make Its Mark

By Barbara Korp
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When it comes to watches, enthusiasts tend to throw the word “legend” around pretty liberally, but some models, such as the Rolex Daytona, really do deserve the title. Despite the model’s initial difficulties, there are few watches more popular today. Yes, the Daytona’s popularity can be traced to Hollywood star Paul Newman, but it also owes its success to Zenith’s El Primero movement, one of the few calibers to warrant being called a legend in its own right. The El Primero was the driving force behind the very first automatic Daytona. Let’s take a look a what sets this movement apart and how it helped write the Rolex Daytona’s success story.

The Rolex Daytona – an icon in the watch world

The El Primero: A Revolutionary Movement

Our story begins in the 1960s, a time when hand-wound chronographs prevailed. The reason for this was that the chronograph cadrature and automatic winding mechanism stood in each other’s way within a movement. Zenith was one of many parties seeking to rectify this issue. Seiko was also working to develop an automatic chronograph movement, as was a team headed by Breitling and Heuer. In the end, Zenith was first to release its solution in 1969 – enter the El Primero, i.e., the first. The caliber’s name doesn’t only signify that Zenith won the race to develop the world’s first automatic chronograph movement, but also clearly articulates Zenith’s claim as a leader in the Swiss watch industry.

One of the El Primero’s major strengths was obvious at first glance: Measuring just 29.33 mm across and standing 6.5 mm tall, the caliber could easily be fitted into many watches. These dimensions were made possible by integrating the winding mechanism into the chronograph caliber. Moreover, the movement boasted a more than 50-hour power reserve thanks to the use of a relatively large barrel and a rotor that wound in both directions. These achievements are extremely impressive when you consider that at the time, most hand-wound chronographs had power reserves of 35 hours or less.

Early Criticisms

Despite these impressive specs, the El Primero didn’t receive overwhelming positive feedback. In fact, some of its major strengths – its complexity and high frequency – were subject to criticism. The base movement was comprised of 280 individual pieces, posing quite a challenge for watchmakers. The automatic chronograph movements that followed in subsequent years all had around 100 fewer parts. Servicing and maintaining the El Primero required special care and expertise, and frequently more expense. As is often the case with innovation, the higher frequency raised some eyebrows. Some voiced concern that the rapid speed would make the oil literally fly off, leaving key components without lubrication. A dry lubricant was quickly developed in response, which satisfied most critics.

Others criticized the caliber’s unusual means of operation. For starters, the time and quickset date were located in unconventional places. When you pull the crown out, you can adjust the time on the first click, and the date on the second – the exact opposite of most timepieces. The seconds hand also continued to run even when the crown was pulled out, making it more difficult to set the time precisely.

The El Primero – still a technical marvel to this day

Early Success and Use in the Rolex Daytona

Despite the criticisms, many watchmakers agreed that the El Primero set new standards for chronographs, and chose to employ it in their own models. Some of these brands included Ebel, TAG Heuer, Panerai, Parmigiani Fleurier, and Rolex. It was an atypical move for the latter brand with the crown, but now you wonder if there would’ve even been a new edition of the Rolex Daytona without the El Primero. The brand started using a modified version of the caliber in its Daytona in 1989. The biggest adjustment Rolex made was reducing the frequency to 28,800 vph in fear that the higher frequency would damage the movement itself. The date display was also omitted, and the escapement system adapted to meet Rolex standards. Afterward, the movement was marketed as the caliber 4030.

While the modified caliber with its reduced frequency didn’t fully capture the sheer fascination of the El Primero, it did set off the Daytona hype. For the first time, Rolex’s chronograph was available with a high-quality automatic movement, making it much more attractive to many wearers. Thanks in large part to the movement’s high technical standards, Rolex Daytonas were powered by the El Primero for more than a decade. It wasn’t until the new millennium that Rolex finally unveiled a Daytona with the in-house automatic caliber 4130. To this day, Zenith is proud of the fact that it outfitted one of the industry’s most famous watches for so long – and rightly so. There are few honors so great as having your movement bought by the brand with the crown.

The El Primero powered the Rolex Daytona for more than a decade.

The Success Story Continues

So, where did the El Primero go from there? In 2017, Zenith introduced the new El Primero 9004, which can time hundredths of a second rather than just tenths. This level of precision is usually reserved for quartz watches! Then in 2019, expectations were high in the run-up to the caliber’s 50th anniversary. The results were as impressive as they were disappointing. Zenith presented the El Primero A386 Revival in yellow, white, and rose gold, which featured a reconstructed but modernized version of the original movement. So sure is Zenith of their manufacturing prowess, that buyers could purchase these watches with a 50-year warranty. As fascinating as the watches were, they weren’t readily available to the general public, which left some fans with a slightly bitter aftertaste.

Zenith El Primero A386 Revival in yellow gold

The watch community recovered when Zenith released the El Primero 3600 in the Zenith Chronomaster Sport. When the watch was introduced, it was immediately compared to the Rolex Daytona; some even suggested that Zenith tried to ride on the coattails of the Daytona hype. But hang on, wasn’t Zenith partially responsible for the Daytona’s popularity in the first place? Of course, the brand is proud of the connection; it’s only natural that it would want to give a nod to this historical milestone. Plus, the Chronomaster Sport is much more than just an alternative to the Rolex Daytona; in some ways, it’s superior. Not only is the frequency kept at the standard 36,000 vph, but the movement can measure tenths of a second and display them in a totally new way.

Zenith Chronomaster Sport

The central chronograph hand only needs 10 seconds for a complete rotation and can be read using a 100-point scale on the bezel. Moreover, there is a 60-second display on the subdial at 3 o’clock. Across the dial at 9, you’ll find the classic small seconds, and at 6, a 60-minute counter. The hand on the latter subdial moves smoothly rather than jumping from minute to minute like on other models.

The real technical masterpiece in this movement is finding a way to have the seconds hand complete a 360-degree rotation with 100 steps in just 10 seconds. This required all the movement components down to the shape of the gears to be redesigned! This movement has nothing to hide; it can be viewed in all its glory through the sapphire crystal case back. Be sure to look out for the blue column wheel and open rotor featuring the Zenith star. Still hung up on the visual similarities to the Rolex Daytona? Or does that pale in comparison to this perfected version of the El Primero? You’ll have to decide for yourself!

Zenith Chronomaster Sport
03.3100.3600/69.M3100 ()
Case material

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While the Rolex Daytona is the grail watch for countless watch enthusiasts, it’s still worth taking a look at the current El Primero chronographs. Not only will you avoid the crazy wait times, you’ll also find there are plenty of elegant and sporty models to suit any taste. Fascinating technical details aside, you’ll be getting the very same experience as wearing those early El Primero models. The movement’s high frequency not only translates into the seconds hand gliding smoothly across the dial, but it also offers an acoustic treat if you hold the watch up to your ear. Once you’ve worn an El Primero chronograph on your wrist, it’s hard to avoid adding one to your collection. There are very few timepieces out there that offer a more enjoyable overall wearing experience.

About the Author

Barbara Korp

The moment I learned that watches were a lot more than just simple jewelry, I was hooked; I become enamored with the elegance of timekeeping. But there was one small hitch: most models were just too big for me to wear! That didn't discourage me, however. In fact, I developed quite a niche interest.

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