The Rolex Caliber 2230/2235 Movement | BeckerTime

The Rolex Caliber 2230/2235

In 1999, Rolex began the transition from their highly successful Caliber 2130 series of calibers, the second generation of movements crafted specifically for the ladies’ watch range, and started the role out of its replacement, the Caliber 2230.

Although the earlier series, from its launch in 1983, had gained the distinction of the highest first time pass rate of any caliber tested at the COSC, the Official Swiss Chronometer Testing Institute, that clearly wasn’t accolade enough for Rolex.

A company renowned for its tireless pursuit of excellence, it had continued to fine-tune and perfect their precision engineered components to extract every last ounce of performance. Proof, if it was needed, that Rolex is only in competition with itself and its own ambition.

The Third Generation

The Caliber 2230 can trace its lineage back to the big brother of all modern Rolex movements, the Rolex Caliber 3135. The brand’s most widely used caliber, it serves as the jumping off point for all subsequent mechanisms, a rock solid foundation to which various complications can be added as and when necessary.

However, what makes the 2000 series of ladies’ calibers all the more impressive is their size. While the 3135 is noted as being a relatively large movement, with a 28.5mm diameter that offers at least something in the way of forgiving tolerances and inherent robustness, the 2230 shaves a formidable 8mm off its dimensions.

Squeezing the required number of parts into such a diminutive shell, while maintaining the sort of precision and reliability on which Rolex has built its unassailable reputation, is equal parts art form and engineering marvel.

The Caliber 2230 vs. the Caliber 2130

There are vastly more similarities between the 2230 and its predecessor than differences. Both self-winding, automatic movements share a balance frequency of 28,800BPH, giving the trademark eight ticks per second sweep of the seconds hand. Both have a power reserve of 42 hours, and each are fitted with a Glucydur balance wheel and a Breguet hairspring with overcoil. But, where the mainspring in the earlier Cal. 2130 was just 1.23mm thick, for the 2230, it has been widened to 1.46mm with a corresponding increase in the size of the barrel arbor. It lends the later series of movements a greater shock resistance and an even higher level of timekeeping precision.

The larger components brings about a minute change in the overall dimensions, with a height of 5.95mm for the Cal. 2230, as opposed to the 5.83mm of the older caliber; still plenty small enough to fit inside the elegant cases of Rolex’s women’s collection. Other than these outwardly minor changes, and a jump from 29 jewels to 31, the two series’ are remarkably alike.

But, just as the second-generation movement had taken the record for highest number of first time passes at the daunting COSC tests, the 2235 takes the gold star as the most consistently accurate caliber the Swiss institute has ever certified.

The Rolex Caliber 2230 at Work

Obviously satisfied with the results of all their hard work, at least for a little while, Rolex used the Caliber 2230/2235 in well over one hundred different references.

The no-date 2230 powered the ladies and mid-size Oyster Perpetual range from its introduction in 1999 until it was superseded by the 2231 in 2014. The most classically simple, timeless Rolex, the new caliber slotted comfortably into the gap left by the 2130.

The Rolex Caliber 2235

For the Caliber 2235, with its additional date function, it effortlessly took over where the 2135 had been, as the faultlessly reliable engine inside great swathes of the Datejust family. The 26mm Lady-Datejust, the 31mm midsize and the 34mm Datejust Pearlmaster were all driven by the updated movement.

In addition, the 35mm Yacht-Master, released in 1994, also found the ideal partner in Rolex’s third generation ladies caliber.


There’s never been any question of Rolex resting on their laurels. Their relentless focus on constantly refining their output has seen them maintain their position as the world’s most distinguished watchmaker for generations.

The 2230 is a perfect illustration. It replaced and improved upon, if only by a tiny amount, a caliber that was already the best ever tested to some of the most rigorous standards in the industry.

By endlessly pushing themselves to always do better, Rolex set the standard for others to follow.

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