Ronda 4139

Ronda 4139 | - The Movement Archive

Ronda 4139


This Ronda “Ronda-Matic” selfwindig movement, caliber 4139, was made in the warly 1980ies. It was part of the caliber family 413x/423x/433x/443x, which was produced in different sizes, ranging from 8 3/4 up to 12 lignes, and was available as handwind and selfwindig versions. The calibet 4139 winds in one direction and uses a swiss lever movement, although it is signed as “RL”, which normally stands for Ronda pin-lever movements.

It offers all possible kinds of indications, hour, minute, second, date and weekday (in names as well as in digits from 1 to 7). The date can be quickset by a very unique mechanism: When you set the time backwards, the date advances every 30 minutes.

A big thanks to Mr. Stahl from the Ermano Uhrenwerke GmbH for identifying this movement and providing me very interesting details about it.

Technical data

Size:8 3/4'''
lift angle:52°
Number of jewels:21
Escapement:Pallet lever
Balance types: Nickel anular balance
Shock protection(s): ?
Balance bearing / direction hairspring:Counterclockwise
Moveable stud:yes
Adjust mechanism:Hairspring key
  • SC? (center seconds (type unknown))
  • QG (date indication (aperture))
  • JG (weekday indication (aperture))
  • RDR (date corrector)
  • AUT (selfwinding)
Production period:198x
Datasheet: calibers 4131-3349

Usage gallery

Ronda 4139: Pomar Automatic ladies' watch

Pomar Automatic ladies' watch