Omega Caliber 2500 Complete Guide

Omega caliber 2500

Omega Caliber 2500 Complete Guide

In recent years, Omega has focused more and more on developing and manufacturing its very own in-house calibers. Earlier, Omega used a lot of off-the-shelf movements from manufacturers such as ETA and then modified them according to needs and requirements.

In developing your own in-house calibers, you also need to come up with technology solutions that give the movement characteristics that you would want. In terms of movements, this often relates to anti-magnetism, power reserve, durability, and resistance to shocks, to mention a few.

So what if you combine an off-the-shelf ETA movement with your own developed technology? Then you have the Omega caliber 2500.

In this post, we will go into detail of the Omega Caliber 2500.

Omega caliber 2500

The Omega caliber 2500 is, at its core, an ETA movement, modified by ETA. It is originally born as the ETA 2892, and then modified to become the Omega Caliber 2500. So with that said, unlike what the name might suggest, it is not an in-house movement. But then again, what exactly is a truly in-house movement? Swatch Group, after all, owns both Omega and ETA.

Omega Caliber 2500
Photo by Urdelar.se

The major change with the movement is that it is equipped with Omega’s Co-Axial escapement. The reason why this movement is so notable and historically important is that it is the first movement commercialized with the Co-Axial escapement. The Caliber 2500 was originally introduced to operate with a frequency of 28800 but was then changed to operate at the rather unusual 25,200 vibrations/hour, which Omega determined to be optimal. The rate was changed from generation C and onwards. Reducing the frequency means less wear on parts and thus longer service intervals.

Omega caliber 2500
Photo by Urdelar.se

The Caliber is an automatic mechanical movement and was introduced in 1999. The movement has a free-sprung balance and operates within COSC of -4 to +6 seconds per day. The movement has a power reserve of 48 hours. It has a diameter of 25.6mm and displays hours, minutes, seconds, and date.

Omega Caliber 2500 Co-Axial escapement

Omega invested heavily in the development of the Co-Axial escapement, so the release of the new escapement technology is a huge technical feat for the brand.

Omega co-Axial Escapement

The Co-axial escapement was invented by George Daniels and patented by him in 1974. He then sold the technology to Omega.


”The Co-Axial escapement functions with a system of three pallets that separate the locking function from the impulse, with the pushing, as opposed to the sliding friction of the lever escapement, resulting in greater mechanical efficiency. The critical virtue of this escapement is the virtual elimination of all sliding friction, theoretically resulting in greater accuracy over time and longer service intervals.”


Omega Caliber 2500 generations

The movement comes in the versions 2500A, 2500B, 2500C and 2500D. It is relatively easy to see which version a watch has by looking at the font of the date.

Omega Caliber 2500A

This was the first generation 2500 caliber form Omega, and also the movement that was in production the shortest period of time. The reason for this is that it had some issues with reliability. A common issue with the movement was that the Co-Axial escapement can cause damage to the escapement if subject to shocks at it does not have any shock protection, resulting in the watch to stop. When the movement was released, the technology was not proven, which resulted in the production of this version not reaching any large production numbers

Omega Caliber 2500B

The Omega caliber 2500B can be found int he first generation Aqua-Terra which was released in 2003. This movement was refined and improved with new materials for some of its parts. It still showed some tendencies of issues, but to a far less degree than the predecessor.

Omega Caliber 2500C

The Omega Caliber 2650C was released in the Planet Ocean and was yet improved again. This movement is not a movement that struggles with a lot of issues. It is also the movement that got the new, reduced operating rate of 25200 BPH. This movement is the closest in design and structure to the caliber 8500. It got a new escapement wheel on three levels.

Omega Caliber 2500D

The Omega Caliber 2500D is the last, and most modified version of them all.

Omega Caliber 2500 specifications

  • Frequency: 28800, later changed to 25200 BPH.
  • Jewels: 27
  • Power reserve: 48 hours
  • Technology: Co-Axial escapement
  • Displays: Hours, minutes, seconds, date
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