With this watch, the brand wanted to beat the world record for the lightest mechanical watch once and for all. An exceptional creation, the RM 27-01 pushes the concepts of lightness and strength to the ultimate extreme. The record was smashed in 2013 with this watch weighing exactly 18.83 grams, including the strap, which is the heaviest part. This was a huge challenge.
The RM 27-01 Rafael Nadal has a baseplate attached to the case by four braided steel cables just 0.35 mm in diameter. This structure combines strength and flexibility to protect the movement, which weighs just 3.5 grammes, thanks to the use of grade 5 titanium for the baseplate and tourbillon carriage, and of aluminium-lithium for the barrel bridges and gear-trains.
These cables are held taut by means of an ingenious mechanism of tensioners (located at 3 and 9 o’clock) and pulleys, which act like pylons positioned at the four corners of the movement. Each cable is fixed to the tensioner, and passes over the upper pulley and into the movement, before returning via the lower pulley to finish in the lower flange. Once the watchmaker has threaded the cables, he tensions them by rotating the central tensioner ring with a special tool.
The installation and tensioning of the cables are extremely delicate operations. Excessive tension could break the cables and attachments at any time and damage the movement, while insufficient tension could put the movement into a resonance phase, disturbing its chronometric performance. Designed to stay in suspension inside its case, this exceptional caliber can withstand accelerations of over 5,000 g.