Zenith G.F.J. Calibre 135 Background
Vintage

Zenith G.F.J. Calibre 135 Background

By quattro · Apr 6, 2025 · 45 replies
quattro
WPS member · Zenith forum
45 replies7632 views21 photos
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Emmanuel, known as quattro on WatchProSite, delves into the historical significance and technical prowess of the Zenith Calibre 135. His original post meticulously details the movement's inception and design philosophy, highlighting its purpose-built nature for the rigorous Neuchâtel Observatory competitions. This foundational exploration provides crucial context for understanding one of Zenith's most celebrated chronometer movements.

For this thread, I’m testing a new presentation mode with the text coming gradually with the photos.


Best to you all, Emmanuel


A/ Zenith Calibre 135


Presented in 1948, the Zenith Calibre 135 was created by Ephrem Jobin (born in 1909, cf. image below) and specifically developed to meet the norms of the Neuchâtel Observatory competitions.



(credit: monochrome)

The caliber 135 was designed with a 30 mm diameter (the maximum dimension to enter the wristwatch category competition) and a 5 mm height. The idea was to have an extremely large 14 mm balance wheel to enhance precision and rate stability, and a large barrel to deliver consistent power to the regulator.


This movement also enabled the brand to win numerous chronometry awards: it garnered 230 honours, many of which were first prizes, including five consecutive first prizes for chronometry in the wristwatch category (from 1950 to 1954) certified by the Neuchâtel Observatory.








(credit: SteveG on ninanet.net)  


B/ The 2022 Phillips-Voutilainen-Zenith Calibre Observatoire Limited Edition (10 pcs), ref. 40.1350.135/21.C1000


Among  the different versions of the Zenith Calibre 135, the 135-O movements were iterations made solely for participating in chronometry trials at the Observatories of Neuchâtel, Geneva, Kew, Teddington and Besançon.




(credit: monochrome)  


Ten of these original observatory-tested 135-O movements, belonging to the historical 1950-1954 serial winning years, have been restored in 2022 for a modern limited edition released by Zenith in collaboration with Phillips and Kari Voutilainen. The ten watches have a 38 mm 950 platinum case.





Above: the Zenith Calibre Observatoire (right) with a vintage Port Royal Chronomètre powered by Calibre 135 (left)














(credit: monochrome)


C/ Zenith's new G.F.J. Calibre 135, ref. 40.1865.0135/51.C200

For Watches & Wonders 2025, Zenith releases a limited edition of 160 pcs named after the initials of the brand’s founder Georges Favre-Jacot (G.F.J.).


The case is made of 950 platinum and measures 39.15 x 10.15 mm with 45.75 mm lug-to-lug.


The dial is made of blue bricks guilloché on the outer ring, lapis lazuli in the centre and blue mother-of-pearl small second counter (18k gold applied indices & faceted hands).


The watches are powered by a reworked version of calibre 135 with 160th anniversary bricks guilloché decoration. It is, of course, chronometer certified and beats at 18,000 vibrations/hour (2.5 Hz). Power reserve is 72 hours.


Three straps are delivered with each watch: a dark blue alligator leather strap with platinum pin buckle, black calfskin leather and blue Saffiano calfskin leather. Upon request, an optional platinum bracelet with double folding clasp is available.


















(credit: monochrome)


Key Points from the Discussion

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The Discussion
QU
quattro
Apr 6, 2025

Yes, this photo of Ephrem Jobin is really wonderful. Best, Emmanuel

PA
patrick_y
Apr 6, 2025

Thank you for the introduction and the connection to history. This is a nice piece. But the fact that the new movement is not a direct copy of the original; losing a lot of the charm of the original which has a better regulator adjustment system and a cooler balance wheel with more weights, I'd say this piece is very nice, but hard to justify that 80,000 Euro price tag.

BL
blau
Apr 6, 2025

I'm sure I'm starting to sound cranky and repetitive but: Zenith MUST do a 135 with a steel case and straightforward decoration for an accessible price. $50-$100k platinum handmade whatnots are just not what I, or, I believe, Zenith's collectors at large, are looking for.

SA
SALMANPK
Apr 6, 2025

monochrome-watches.com

PA
patrick_y
Apr 6, 2025

Thank you for catching the mistake!

SA
SALMANPK
Apr 6, 2025

Maybe with the tariff your number might be right 😋

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