|Winding:||Automatic, Bi-Directional Automatic Winding, Central Rotor Automatic Winding|
|Diameter:||28.50 mm (12.5 ligne)|
|© Rolex||Complications:||Date, Day, Hacking Seconds, Hand Winding, Outer Day Wheel, Quick Date Correction|
|Hands:||Central Hour Hand, Central Minute Hand, Central Seconds Hand, Date Window at 3:00, Day Window at 12:00|
|Distinguishing Technical Characteristics|
Clockwise Balance Cock
|Production: 1977 – 1988|
Cal. 3055 was the fifth-generation Day-Date movement, produced from 1977 through 1988 and used in the famous “President” Day-Date watch model. It was part of the Rolex 3000 family of movements, developed alongside the Oysterquartz Cal. 5000 series with which it shared many components. Cal. 3055 was retired in 1988 in favor of the updated Cal. 3155.
- Rolex Day-Date, Ref. 18000, 18026, 18028, 18029, 18038, 18039, 18046, 18048, 18049, 18078, 18079, 18178, 18206, 18208, 18238, 18239, 18248, 18249, 18308, 18348, 18368, 18369, 18388, 18389
Compared to the predecessor Cal. 1556, Cal. 3055 was much-improved. The balance speed was increased from 19,800 to 28,800 A/h and it gained a quickset date feature, though it only advances the date wheel. The hacking balance wheel features a Breguet overcoil and Microstella regulation.
It is a 28,800 A/h 12.5 ligne movement with bi-directional automatic winding and chronometer certification. The movement is 28.5 mm in diameter, with 27 jewels. It has a power reserve of 48 hours. The date is quick-set in crown position 2 but the day function is not quickset as on later movements. Note that many sites list the thickness or height of the movement at 6.3 mm but the official Rolex parts diagram shows it as 7.11 mm.
The movement can be manually wound with the crown in position 1. Rotate the crown clockwise to wind the mainspring.
The date wheel is advanced with the crown in second position (one notch out). Turn the crown counter-clockwise to advance the date wheel by one day.
The time is set with the crown in third position (pulled all the way out). Rotate the crown counter-clockwise to advance the minute and hour hands and clockwise to turn them backward.
|3000 Family||3100 Family||Parachrom Family||Chronergy Family|