Zenith Defy Classic Chronograph Men's Watch 03.0526.4000.21.R642

GMT- Printemps-Ete 2010

A few issues ago, we had subjected Zenith's Defy Extreme Chronograph to the testing bench. The legendary El Primero movement had lived up to its reputation, with the main surprise coming from the exterior which certainly justified the nickname "Extreme". At Baselworld 2009, the manufacturer from Le Locle had presented a model in its "Grande Class" collection that represents a mechanical extrapolation of the El Primero, this time extreme in terms of its superlative movement.
It is thus with great respect that we took a closer look at the Zenith Grande Class Tourbillon Moonphase - a name which, despite its length, is far from exhaustive in terms of the functions offered by this model.
The exterior:
Over the past two decades, the style of in-house-made watches has evolved towards volumes built on gentler, minimalist lines. This design evolution has resulted in a tendency to accentuate essentials. The exterior thus matches the beautiful internal mechanics, setting them off to their best advantage by providing an understated elegance that is probably most closely rivalled by watches from the 1920s and 1930s - at least in this writer's opinion. One of Zenith's key strengths lies in its consistent ability to play a pioneering and even visionary role. I am completely spellbound by the efficiency and the simplicity of the lines of the case, even though this should not really surprise me. The overall 15 mm height is perfectly proportionate to the 45 mm diameter, creating what seems an entirely reasonable volume that is ideally in tune with current trends. The all-polished case of the model being tested was made from 750 rose gold. As one has come to expect from El Primero models, the position of the ovoid pushers close to the crown contributes to the balanced overall aesthetic, further enhanced by the symmetrical 9 o'clock positioning of the moon corrector.

The gold dial is hand-guilloche with various motifs and embellished by splendid rose gold numerals and hour-markers. The ingenious layout of the various indications, on which we will focus in the following section, ensures good visibility and a clear-cut separation between the functions. The caseback is fitted with an off-centred sapphire crystal revealing the base movement.
The movement:
Although this set of complications is a first for Zenith, the movement is nonetheless the iconic El Primero with its traditional functions of self-winding tenth of a second chronograph with 30-minute and 12-hour counters. The Zenith movement design engineers have displayed sheer genius in arranging the other complications. Although fully and perfectly integrated within the movement, they have been arranged around the circumference of the ultimate "base" movement, El Primero. This wise choice results in the above-mentioned balanced proportions and readability without the various complications overlapping to the detriment of clarity. The magnificent tourbillon carriage occupies part of the space generally taken up by the regulating organ, and extends beyond it into the upper left-hand part. This has made it possible to maintain the size and balance inertia required to achieve the legendary frequency of 36,000 vph. We will see what the tests reveal when this set of components is placed within a pivoting tourbillon carriage, but just thinking of it is enough to make your head spin. The date indicator, which is adjusted with the stem pulled out to the second notch, reminding us that this is a real El Primero calibre, features a smaller size and is placed concentrically with the tourbillon carriage. In order to maintain the space-saving in terms of overall thickness, the moon-phase indicator is also placed beyond the circumference of the base movement and is displayed in the lower left-hand part of the dial. The latter's gold and enamelled decor is both discreet and effective. The 335 parts of this Calibre 4034 increase its diameter by a mere 5.50 mm. 

And before the eagerly awaited test results, we should specify that the decoration and finishing are, as always with Zenith, entirely irreproachable.
Tests

We were expecting the results to be good, and they proved to be excellent! It is always a pleasure to test a tourbillon, because the process involves only two measuring positions. When fully wound, the amplitudes in a horizontal position were measured at 291-92° and between 254 and 257° in vertical position for five minutes. These high amplitudes for a 36,000 vph model are exceptional. What is even more amazing is that after 24 hours of operating, the amplitudes were measured at 268° in horizontal position and 234° in vertical position, while the rates proved even more accurate: 1 second/day in a vertical position (again averaged over 5 minutes) and +2 seconds/day in a horizontal position! What more could one expect? Since this is a chronograph with an intermediate wheel rather than a clutch, the resulting loss of amplitude only actually occurs when the chronograph is activated. We measured this loss 20 times corresponding to varying degrees of winding, and the largest loss of amplitude was 10°.
Since the energy consumed by the moon-phase indication is insignificant (one tooth/day), one would expect the tourbillon carriage to use a lot more. The guaranteed autonomy is 50 hours, but our power-reserve test measured it at around 53 hours, thus definitively settling that issue.
 
The Grande Class Tourbillon Moonphase is extremely comfortable on the wrist and makes a beautifully balanced fit, particularly thanks to the choice of a triple-blade folding clasp. Handling is also easy. The chronograph controls remain a benchmark. Overall legibility is excellent, although reading the date in its dedicated aperture calls for good eyesight and a certain amount of time. Finally, the very fact that this product is so good inspires me to underline a minor flaw, as it seems a pity that the chronograph seconds hand rack should be interrupted by the passage of the moon-phase window and the tourbillon.
 
Conclusion:
The understated discretion and aesthetic appeal of the Zenith Grande Class Tourbillon Moonphase might almost make one lose sight of the technical importance of this mechanical masterpiece which significantly contributes to pushing the borders of precision.
After such a magnificent achievement, perhaps the only challenge Zenith will not need to meet with this new model will be selling the ten rose gold and five white gold watches in this "confidential" series.