The RM UP-01 Ferrari, an unprecedented wristwatch made possible by Richard Mille's expertise

Bulgari led the race to develop ultra-thin mechanical watches. The ultimate winner was Richard Mille's RM UP-01 Ferrari. Released in 2022, this model has a case thickness of just 1.75mm. Who would have expected that Richard Mille, known for its lightness and strength, would break the record for thinnest watches? However, this was an entirely new ultra-thin watch, including its unique case structure, that only Richard Mille could create.

A sturdy case that doesn't feel thin, shock-resistant, and portable precision

　Since the 2010s, manufacturers have worked to improve the performance and make their movements thinner. The approach is generally the same regardless of manufacturer. By widening the baseplate, components are distributed throughout the movement, and the automatic winding mechanism is also incorporated within it. This technique has been around since the 1970s, but it can be said that it has been largely perfected in recent years, when larger movements have become acceptable. Bulgari was the one that took this technique to the extreme. The ultra-thin movements made by the company stand out for their approach of not stacking movement components. The culmination of this work is the 1.80mm thick Octo Finissimo Ultra, released in 2022.

　The RM UP-01 Ferrari, which broke the Octo Finissimo Ultra record for thinness in the same year, also used the same design concept, but by arranging the gear train, function selector, and winding and time-setting mechanisms in parallel, the case was just 1.75 mm thick, 0.05 mm thinner than the Octo Finissimo Ultra.

　With a width of 51mm, height of 39mm, and a case as thin as a coin, the RM UP-01 might not seem like it would be suitable for everyday wear. However, my impression after actually handling it was that the case was surprisingly sturdy for an ultra-thin mechanical watch. In fact, like existing Richard Mille models, this model can withstand an acceleration of 5000G, and the case will not deform even when a load of approximately 12kg is applied to the outer periphery.

　Using a harder material like ceramic would have made the 1.75mm flat case more rigid, but Richard Mille didn't take that approach. The case is made of the same titanium as existing models. While the case is prone to bending, the company's expertise lies in preventing this.

　The unique case structure is what gives the RM UP-01 its high rigidity. The lid is sewn onto the box-shaped case, preventing distortion. In addition, the case opening has been made smaller, making it even more robust.

　This attention to practicality can also be seen in the way the function selector and the winding and time-setting mechanisms are fixed. These two parts essentially function as a crown. To improve water resistance, a watch would normally have rubber wrapped around the shaft, but the RM UP-01 instead uses a thin ceramic frame. While theoretically it can be made thinner than rubber, achieving 10m water resistance through the interlocking of parts alone would not be possible with ordinary parts. This is a solution only possible at Richard Mille, who processes cases down to the micron level.

　What makes this watch unique is the way the hours and minutes are displayed and the escapement. In a normal watch, the minute hand is attached to the second wheel, and an intermediate wheel is attached to that to turn the hour hand. In the RM UP-01, by using two gears to represent the hour and minute hands, not only has the thickness been reduced, but by placing the axis against the crystal, deformation of the crystal is also suppressed. It is also extraordinary that the crystal was made thick while the hour and minute displays were made thin. The sapphire crystal, which is 0.45mm thick compared to the case, contributes to increasing the rigidity of the case.

　Another point of interest is the new escapement. Even in thin watches with components arranged in parallel, the escapement has traditionally been the conventional Swiss lever. In contrast, the RM UP-01 uses an ultra-flat escapement that does away with the point and rib. This not only allows for a higher oscillation angle, but also makes it possible to make the escapement itself thinner. The balance wheel is quite thin, but its moment of inertia is unexpectedly large at around 3 mg/cm2. By increasing the frequency to 8800 vibrations per hour, portable accuracy has been improved.

　The RM UP-01 Ferrari is not only an ultra-thin mechanical watch, but also practical enough for everyday wear. Assembling a watch of this caliber would be even more difficult than existing thin watches. However, Richard Mille is producing not just 15, but 150 of this model. This watch breaks the record for ultra-thin watches not only in quality but also in quantity, making it a watch that only Richard Mille could make, a "mechanical wonder" of the 21st century.