The new Cal.3255 launched in the year of 2015 has essential difference when compared with the Cal.3155 movement, but not beyond the categories of movement types, they all exclusive movements of the Rolex Daydate watches. So where is the difference? I think for most of the differences, everybody had already known at the beginning of the year, such as Clockwork box wall being 50% thin, using the new paramagnetic Chronergy escapement system to improve the efficiency of 15%, escapement fork watts being 50% thin when compared with the previous generation, dynamic store increasing to 70 hours, redesigning or changing more than 90% of the movement parts, two times accurate than the original observatory authentication, owing 14 patents, and so on. But there is one more detailed change that little people know, this change is not big nor small, but very conspicuous, in fact it should not be ignored, that is the micrometer adjusting screw on the bridge plate.
Speaking of the micrometer adjusting screw, it appeared in 3 XXX based movement for the first time, but not launch until 2015, so it is not a new technology, but for Cal. 3235 or Cal. 3255, it is an important change. Before talking about the micrometer adjusting screw, we start with the micrometer adjusting screw hide under it, in Cal. 3235 / Cal. 3255, the balance wheel bridge plate has very obvious changes when compared with the last generation, The function of the screw, is by adjusting the position of the swing bridge plate, to adjust the amount of balance wheel clearance, in the process of installation, the position deviation of the bridge plate will directly affect the position of the pendulum, which affects the time. These two micrometer adjusting screw can be seen from the 30 xx single bridge board to the 31XX movements. And it helps to guarantee the stable performance of the Rolex watches.