Rolex Caliber 3285

Manufacturer	Rolex
Caliber Number	3285
Movement Type	Automatic, self-winding mechanical
In-House?	Yes
Diameter	28.5mm (needs confirmed)
Jewels	31
Total Parts	Unknown (please add to comments below)
Power Reserve	70 hours
Vibrations Per Hour	28,800 (4Hz)
Rotor Winding Direction	Bidirectional
Hand-Windable?	Yes
Hand Winding Direction	Clockwise
Balance	Paramagnetic Oscillator
Escapement	Chronergy
Shock System	Paraflex
Hairspring	Paramagnetic blue Parachrom
Features	Central hours; central minutes; central sweeping seconds; central GMT hand; date at 3:00
Hacking Seconds?	Yes
Country of Manufacture	Switzerland, Swiss made
Known Models	Rolex GMT-Master II (ref: 126710BLRO, 126711CHNR, 126715CHNR, 126720 Lefty, 126713GRNR 18K Gold/Steel Two-Tone, 126718GRNR solid 18K gold), Explorer II (ref: 226570)

Baselworld 2018 Introduction:

The Rolex caliber 3285 was the only new Rolex movement announced at Baselworld 2018.

In Rolex’s own words:

“With 10 patent applications filed over the course of its development, this self-winding mechanical movement is a consummate demonstration of Rolex technology, at the forefront of the art of watchmaking. Calibre 3285 offers fundamental gains in terms of precision, power reserve, resistance to shocks and magnetism, convenience and reliability. Calibre 3285 incorporates the Chronergy escapement patented by Rolex, which combines high energy efficiency with great dependability. Made of nickel-phosphorus, it is also insensitive to magnetic interference.” -Rolex.com

3285 vs 3186:

The new caliber 3285 movement replaces the caliber 3186. It has a larger overall diameter allowing for a larger barrel offering a 70 hour power reserve. The caliber 3285 also has the updated Chronergy escapement allowing for 15% more efficiency as per Rolex claims.

Superlative Chronometer:

Rolex labels the new caliber 3285 as a Superlative Chronometer, claiming that it is two times more precise than an officially certified chronometer with an accuracy of -2/+2 seconds per day “after casing”. Superlative Chronometer is an in-house version of testing that goes beyond COSC parameters.

Lefty GMT-Master II:

The caliber 3285 is also found in the green bezel left-handed (destro) GMT-Master II (Ref: 126720VTNR) that was announced at Watches and Wonders 2022.

GMT-Master II Gold and TT:

At Watches and Wonders 2023 (March 27, 2023), Rolex introduced the Rolesor GMT-Master II (126713GRNR) two-tone in 904L stainless steel and 18K yellow gold, as well as a solid gold version (126718GRNR). Both of these new timepieces are powered by the cal. 3285.

Additional Resources:

• Rolex Explorer II official brochure (pdf)
• Rolex Explorer II user manual (pdf)