There was a time when the only difference between the watches of Rolex and Tudor was the engine inside. Rolex, of course, had all Rolex designed and produced movements and virtually all were submitted to Contrôle Officiel Suisse des Chronomètres (COSC for short), the Official Swiss Chronometer Testing Institute, for testing and certification as chronometers.
Tudor, on the other hand, used the less expensive and readily available ETA movements. Certainly these motors were plenty tough on their own, and on an individual basis were typically able to be tuned to COSC standards.
However, the challenge many brands have accepted these days is that of producing their own in-house calibres. And once done, why not go for the two-point conversion and submit to COSC for chronometer certification?
Whether prompted to do so by the Swatch Group’s coming moratorium on shipping to non-Swatch Group entities, or simply to demonstrate prowess, I’m not quite sure.
But the fact is, Tudor has joined the ranks of brands with an in-house COSC-certified movement – the MT5621.
This movement features automatic winding (of course) with a bi-directional rotor. It’s a basic three-hander, with an instantaneous date change. It allows rapid date setting (what we know as a quick-set), and hacking (stop-) seconds. A really nice feature is the fact that no backlash needs to be accounted for when setting the minute hand.
The 28 jewel movement counts out 28,800 BPH, with the balance wheel oscillating on a silicon balance spring. The balance is held by a full balance bridge, aiding shock resistance and precise alignment.
The whole works is 33.8mm dia. x 6.5mm thick. That’s really pretty huge, considering an ETA 2892 is only 25.6mm in diameter and 3.6mm thick. Some of that diameter has been used to house a mainspring barrel which allows a 70 hour power reserve. That’s a nice thing if you tend to rotate your watches and don’t appreciate having to wind and reset after letting them lay fallow for a couple of days.
The MT5621 comes as the standard motor inside the Tudor North Flag and Pelagos models, and there’s been some grass roots resistance to accepting these watches because of it – at least here in the Midwestern US. Maybe it’s our natural wait-and-see attitude. It’s hard to really imagine the 5621 is anything but a robust calibre, put into two of Tudor’s flag-bearing tool watches.
Time will tell, however.