The IWC 89360 calibre is a self-winding movement with an operating frequency of 28,800 vibrations per hour (4 Hz), 40 jewels and a power reserve of an impressive 68 hours. The chronograph functions (start/stop/reset) are controlled by a column wheel and engagement is via an oscillating pinion. A choice, the latter, which goes against the current tendency to use the vertical friction clutch (which we have analysed at length on several occasions in L'Orologio, on the occasion of the analysis of the Frédéric Piguet, Rolex, Jaeger-LeCoultre and Patek Philippe calibres), but which can be explained when one considers that the same system is used on the ETA-Valjoux 7750, which is used on a large number of IWC creations and is therefore widely experimented and well mastered by the Schaffhausen-based company's watchmakers...
For a description of how the chronograph mechanism works, I refer you to the issue of L'Orologio soon to be on newsstands.
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