Certainly, from an engineering standpoint, the two watches use significantly different movements, although what they do have in common is that both the Zenith 3600 and the Rolex 4130 are very much pieces of contemporary, high-tech mechanical horology.Several years ago, I had the pleasure of touring the Zenith manufacture in Le Locle, Switzerland, and afterward had the chance to speak with representatives of the brand. Whether or not the resemblance bugs you is a matter of taste – I suspect some folks will be put off by it, although considering a modified El Primero movement was used by Rolex for the first self-winding Daytonas, I'd propose that Zenith is, to some extent, entitled by history if nothing else to connect the dots a little. The color and the way the ceramic reflects the light on the Chronomaster Sport is insistently reminiscent of the Daytona bezel, but the typeface and function are quite different – the Daytona has a tachymetric scale and the Chronomaster Sport, graduations for reading off tenths and hundredths of a second. Zenith has used ceramic bezels before in the Chronomaster line, but as far as I have been able to determine, just on the two 50th Anniversary limited edition models (which were also launch platforms for the caliber 3600). I think what makes the resemblance seem so strong at first glance is the ceramic bezel. Zenith has gotten around this problem partly by using low-inertia silicon for the escape wheel, but a lot of the mitigation comes from customization of the driving and coupling wheels, each of which has a unique profile for the gear teeth. The amount of energy available is even less than at the fourth wheel, and adding the load of driving the chronograph is potentially even more problematic. The problem is even worse if you try to drive the chronograph off the escape wheel.

Balance amplitude can drop significantly when a chronograph is switched on, and if the watch isn't in optimum condition, accuracy can suffer if you leave the chronograph on for long enough. Driving a chronograph from the fourth wheel is already kind of pushing it it's the last conventional wheel in the going train, and stealing energy from the gears at that point means less energy is available to reach the balance. The reason you don't usually see chronographs driven by the escape wheel is that, generally, it's a terrible idea to try.

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