Interestingly, the dimensions of the two movements vary only slightly. Each has an impressively long power reserve of more than three days. Plus, both movements are equipped with a bidirectional winding system and have an elegant column-wheel mechanism. But if you examine the movements (and you’ll have to remove the caseback from the Breitling to do this) the differences are immediately clear. While IWC uses the same automatic shock-protection rotor bridge as in its Ingenieur movement 80111, the Breitling appears somewhat more conventional. Breitling wins points with a patented self-centering system for the zero position resetting hammers, a calendar with an instantly advancing date, and especially for the modern vertical clutch that prevents the chronograph seconds hand from jumping when it starts.
Breitling added a shock-absorbing escape wheel to make the watch more resistant to impacts. Another bonus: the movement includes an index-assembly that allows the wearer to quickly and easily adjust the watch’s rate to his or her preferred speed. Breitling also produces its mainplates and bridges in-house, and sets its own jewels as well.
For the 89360 caliber, IWC developed a new double-pawl winding system based on its standard Pellaton winding system. With two double-pawl winders, it doubles the number of pawls that push and pull to wind the mainspring. They are no longer controlled with a cam but by a crank similar to the type used in automobiles. The pawls are arranged to apply winding torque even at the slightest motion of the rotor. This winding system is said to be 30 percent more efficient than its predecessor, making it possible to reduce the weight of the rotor and thereby reduce wear. The movement features a free-sprung oscillating system, a sign of high quality. Plus, the flyback function in the Big Ingenieur Chronograph (not featured in the name of the model, as is usually the case) requires a great deal of time and effort in the design stage. The minute counter does not jump, but advances slowly. Unfortunately, the date disk moves slowly, too, and begins visibly advancing at 11 o’clock.
The two movements are similar in their degree of decoration, with various finishes, perlage on the mainplate and polished screw heads. The cutouts on the IWC rotor provide a nice view of the movement, but few edges show beveling or polishing.
Like the Valjoux 7750, IWC’s movement uses a rocking pinion for its chronograph clutch. This solution was developed in order to simplify the chronograph but has proven to be essential. The axis of the pinion is moved only on one side and causes the wheels to engage. IWC has created a special shape for the 240 teeth on the chrono-runner in order to minimize jumping of the chronograph seconds hand.
Both watches contain stamped and polished levers, which remind us of those on the Valjoux 7750. Machined levers would have been better choices. Both movements therefore show a mixed bag of features, combining high-quality components with parts one usually finds in lower-grade movements.
This combination of different grade components has no negative effect on the rate results at all. Both watches have highly accurate rate results, which one would certainly expect from Breitling with its chronometer certification. The B01, like every Breitling movement, is submitted to COSC, the Swiss regulating authority that issues the certificates, which subjects eeach movement to 15 days of rigorous testing, and each one must conform to the agency’s strict standards. In our test watch the B01 caliber met these standards, with a beat error of no more than five seconds per day between each position and an average deviation of only +0.2 seconds. IWC Caliber 89360 kept up the pace, with an average deviation of +1.3 seconds with the greatest difference only three seconds. Plus, the IWC shows almost these same results when the chronograph is running.