Today, I’ll discuss a technical issue, and it’s why Rolex has applied Syloxi silicon hairspring to the Lady-Datejust 28 and the Yacht Master 37. At present, most of Rolex men’s watches are fitted with caliber 3135 and caliber 3235, and some ladies’ watches by Rolex in small size come with caliber 2236. Calibre 3135 and caliber 3235 both are equipped with Parachrom hairspring, and blue can be seen between 12 O’clock and 1 O’clock in the picture. Caliber 2236 has been equipped with Syloxi silicon hairspring since 2014. What’s Rolex’s intention?



It is well known that Parachrom hairspring is excellent, but why would Rolex develop silicon hairspring? Now that the new hairspring has come out, why would it apply to ladies’ watches by Rolex? Which is better, Parachrom hairspring or Syloxi silicon hairspring? With my knowledge on movements increasing, I can answer the question.

Parachrom Hairspring
First, it’s not denied that Parachrom hairspring is awesome. In general, mechanical movements are fitted with Nivarox alloy hairspring. Nivarox alloy hairspring works well, whose anti-magnetic property and resistance to temperature change both are OK in general living environment. But, its fatal flaw is that the alloy spring consists of an amount of iron. The iron is easy to be influenced by magnetism, so Nivarox spring can’t resist strong magnetic field. This is the reason why most watches become less and less accurate. To solve the issue, Rolex developed exclusively Parachrom spring in 2000. Parachrom spring is made of niobium and zirconium alloy, featuring resistance to magnetism and shock. To be frank, it doesn’t contain iron.

Syloxi Hairspring
In resent years, silicon spring featuring outstanding anti-magnetic property is spread widely, so many mechanical movements are fitted with it, like watches by Tissot and Mido. The act that Rolex decided to develop silicon spring just follows the trend? It’s not true. Even though Parachrom hairspring is awesome, it has a little weakness. The end of the alloy hairspring needs to be fixed to a clamp, so it isn’t a symmetric structure. From a professional perspective, the weakness will influence the accuracy. In the picture, Syloxi hairspring is fully symmetrical. It is made through a chemical way, and the integrated hairspring is fixed to both holes of a bridge plate. Syloxi hairspring has been patented by Rolex, more accurate than Parachrom hairspring. There isn’t a perfect person or item. In case of damage, Syloxi hairspring can’t be repaired, only be replaced by a new one.


The fact is that Syloxi hairspring has better performance than Parachrom hairspring. There are two reasons why caliber 2236 is equipped with Syloxi hairspring. The smaller a movement is, less accurately it goes. So, Syloxi hairspring is to enhance performance and accuracy of Rolex women’s watches. The other reason is that Rolex is experimenting on it. Rolex Lady-Datejust 28 and Yacht-Master 37 are fitted with caliber 2236. After Rolex ensures stable, reliable performance of caliber 2236, it will apply to more movements.