Jaeger-LeCoultre Caliber JLC 899

Jaeger-LeCoultre caliber 899 is a thin automatic movement with 32 jewels and a beat rate of 28,800 vph. According to JLC, each caliber 899 is tested rigorously for 1,000 before leaving the factory.

The example above was found in a Jaeger-LeCoultre Master Control reference 147.8.37.S. As well as this example found in a JLC Master Control Date in 18K gold (reference 176.2.40.S aka Q1542520).

In Jaeger-LeCoultre’s own words:

“The mechanical automatic movement, Jaeger-LeCoultre Calibre 899, offers a 43-hour power reserve. Following in the grand tradition of the Manufacture, Jaeger-LeCoultre Calibre 899 is decorated and assembled by hand.” -source from JLC’s site in 2014 when this post was first published: http://www.jaeger-lecoultre.com/US/en/content/jaeger-lecoultre-calibre-899

And now in 2023:

“Beneath the sapphire crystal case-back, onlookers can admire the Jaeger-LeCoultre Calibre 899 designed, produced and assembled under the same roof at the Manufacture. Benefiting from the Maison’s latest innovations, this movement promises an increased power reserve of 70 hours.” –source

New Vs Old Generation:

At the time of this post (3/2023), the caliber 899 is still found being referenced in the current JLC lineup, however the caliber number has changed to 899AC. Although the two movements are based on the same framework, there are some differences with the 899 shown in the photo above (found in a Master Control ref: 147.8.37.S), compared to newer models with the 899AC. For example, the original calibre 899 was rated for 43 hours of power reserve on a full wind. Jaeger-LeCoultre’s current specs on the cal. 899AC claim 70 hours of power reserve. Another difference seems to be the total number of components. The original was said to have 219 parts, whereas JLC says the new models have 218 parts.

Caliber Confusion:

Rather than simply referring to it as the “new generation” of caliber 899, JLC marketing material should be more clear about the new caliber designation. This issue arises when brands don’t respect the technical knowledge of their customers, and try to over-simplify everything as a result. Even if it was just the addition of an evolution marker such as 899/2 or 899B, in this case 899AC, the new designation should be used consistently across all mentions of usage. You may see other publications separating the two movements by calling the original 899/1 or 899-1, but the community should not have to make such distinctions on behalf of the brand – especially when it is a brand with such history and prestige as Jaeger-LeCoultre.

The 899AC itself is signed “899”, not 899AC (full caliber listing on the way):

This causes confusion for resellers and watchmakers. Of course the argument will be made by some that you should purchase your watch from an AD and only send it back to the manufacturer for service – but that is an unrealistic argument that is much easier to type than to abide by. There will come a time when the 899AC models are no longer sold new, only available as pre-owned pieces, and they will mostly be incorrectly labeled as being powered by a caliber 899.

Brands like JLC should realize that their consumers are watch enthusiasts who appreciate transparency and enjoy learning about the timepieces they spend their money on. Aside from a press-release for the new blue dial Master Control (April 25, 2022), there is no mention of the AC caliber designation on the manufacture’s own site. Search jaeger-lecoultre.com for “899” and you will receive 21 sitewide results. A search for “899AC” comes back with no results found.

Without the evolution marker, it creates Caliber Confusion. Case in point: their own official user manual, linked on every product with an 899 movement, lists the power reserve as 38 hours (even more strange since the power reserve of the original was supposed to be 43 hours). It appears that even the brand is confused, so how can consumers not be? The image below is from the user manual:

Additional Resources:

• JLC 899 official search results