The Rolex Caliber 3055 -

The Rolex Caliber 3055

Modern Rolex movements are variations on the theme of a handful of base calibers, with the company systematically upgrading components as technology progresses or adding functionality where needed. For a brand that produces as many watches as Rolex, it makes sense not to have to reinvent the wheel every time a new model is launched.

In the case of the Cal. 3055 released in 1977, it formed part of the 3000 series of movements that ushered in the high beat frequency era, giving the emblematic flowing seconds hand of all latter day Rolexes.

Like its foundation movement, the 3035, the Cal. 3055 has a balance speed of 28,800vph, producing an eight ticks per second sweep, while also adopting the other party piece of the 3000 series, the Quickset date function. Whereas previous calibers had called for wearers to wind the hands through 24-hours to advance the day of the week, the new movement featured a second position for the crown, enabling it to be pulled out halfway to set the date independently of the time. It was a simple innovation that solved one of the biggest problems for the brand’s calendar watches and was incorporated into every Rolex date caliber by 1983.

Delving into the depths of the Cal. 3055, the 27 jewel, self-winding movement has a 42-hour power reserve and uses the series-wide arrangement of free-sprung Nivarox hairspring with Breguet overcoil and Glucydur balance wheel, regulated by Microstella screws.

With a balance wheel made from beryllium, copper and iron, working together with a nickel/iron alloy hairspring, the 3055 practically eliminates the effects of temperature variation on the movement’s isochronism. The Microstella system does away with the need for balance screws, replacing them with four timing weights placed on the inside of the balance rim—a design that creates greater inertia and less drag, with a more precise adjustment to the rate.

As a free sprung caliber, the 3055’s hairspring is able to contract and expand concentrically, giving it a great deal of stability across different positions and, as there’s no regulator for it to come into contact with, the subsequent reduction in friction reduces the amount of wear on the component.

The Cal. 3055 at Work

An unusual aspect of the Cal. 3055 is, unlike the vast majority of Rolex’s engines, it was only ever used in one model of watch. More general purpose movements from the brand find homes inside a variety of different cases; the 3135, for example, powered everything from the Submariner to the Yacht-Master to the Datejust.

The rare Rolex calibers that are created for just a single piece tend to be the most complicated. The Cal. 4130 chronograph was built specifically for the Daytona; the Cal. 9001 was needed to run the ultra-complex Sky-Dweller. For the 3055, with its dual calendar function, there was only going to be one port of call.

The Day-Date ref. 18038 was the continuation of Rolex’s masterpiece flagship that debuted in 1956. The first wristwatch to display both the date and the day of the week, it was and still is the pinnacle of the brand’s considerable catalog.

For the 1977 edition, the 36mm ref. 18038 was released in 18k yellow gold with a fluted bezel, and came with a new sapphire crystal—a virtually scratchproof shield for the elegant dial. Inside, the Cal. 3055 brought instantaneous midnight changes for both the day and the date but, as a single Quickset movement, only the date could be adjusted with the crown. President wearers would have to wait until the 3055’s successor, the Cal. 3155, to arrive in 1988 for the convenience of a double Quickset function.

Alongside the ref. 18038, Rolex also brought a different slant to the Day-Date when it launched the ref. 18078. While identical internally, the ‘Bark President’ featured a textured dial reminiscent of tree bark that was carried over onto the center links of its bracelet. It remains one of the most unusual and distinctive versions of the piece, even among the countless other finishes in which it has been made.


The Cal. 3055 enjoyed a successful 11-year run, providing the kind of understated reliability that characterized all of Rolex’s 3000 series calibers.

The watches it powered are now considered classics of the era and, as smaller 36mm versions of the legendary President, are highly sought after by both male and female vintage collectors.

A product of the brand’s relentless pursuit of perfection, the Cal. 3055 is a true symbol of engineering excellence.

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