What Is the Inner Story of the Rolex Cosmograph Daytona?

The Rolex Cosmograph Daytona denotes many different things to different people, and one of the most common responses to the watch is frustrating, at least with the steel-on-steel reference 116500LN. The origins of this can be traced back decades, all the way to 1963 when the first Cosmograph chronograph was presented. The first Cosmograph, ref. 6239, was sold slowly at first. Even though chronographs were becoming an extremely significant component of watches, the Cosmograph was not the Belle of the ball that it is now.

The watch has changed dramatically over the years, in some ways and others not at all. The watch has experienced drastic technical evolution in the 57 years between the release of the 6239 and the writing of this story, making the new edition of the Daytona the most advanced chronograph Rolex has ever created.

Rolex Cosmograph Daytona 116500LN Parts


The oyster case of the Rolex Daytona is 40mm x 12.4mm thick and made of corrosion-resistant superalloy, 904L steel, which is known to hold its polish better than standard stainless steel. While 904L steel is not the toughest steel alloy known to man, it does have a higher luster than others and is ideal for a Rolex.  Other manufacturing companies are unable to use this more expensive type of steel and must have their cases manufactured for them. Rolex has an advantage because it manufactures all of its components in-house. The oyster case, as the world’s first waterproof case, has almost become synonymous with the name Rolex. Since its inception in 1926, the patented “oyster” case has been one of Rolex’s most recognizable trademarks. A screw-down bezel, a screw-down case back, and a screw-down crown tighten and lock the monobloc middle case.


The chronograph component adds an extra function to the watch and functions as a stopwatch, allowing drivers to time their laps with eighth-second accuracy. The mechanical chronograph complication in the Cosmograph Daytona was engineered with fewer parts than a standard chronograph, making it a more reliable stopwatch.

As a column-wheel chronograph with a vertical clutch mechanism that provides smoother start/stop and reset action than CAM actuated mechanisms. The large central seconds-hand of the chronograph sweeps across the dial very smoothly in that perpetual motion for which a Rolex is famous. A 30-minute counter is located to the right of the dial at 3 o’clock, and a 12-hour counter is located across the dial at 9 o’clock. These three hands are smoothly operated by the chronograph pushers, which are situated above and below the winding crown on the right side of the case.


The dial has not been modified since the previous model as there was nothing that needed to be improved on the dial design because the Cosmograph Daytona chronograph dial is possibly the most recognizable chronograph dial on the market. Everything has remained the same, from the polished steel hour markers with their luminous fill to the proportions.

The Chromalight display is easy to read because it is made of a long-lasting luminescent material that glows in the dark with a bright blue hue. The word DAYTONA is printed in red and wraps around the top of the small running seconds located at the 6 o’clock position, just like on any Rolex Daytona chronograph.


When it comes to the dial’s silver-rimmed sub-registers, everything has remained the same from the previous model. The small running seconds sub-dial is located at the bottom center of the dial at 6 o’clock. The chronograph is activated by the sub-registers on the right and left sides of this sub-dial at 3 and 9 o’clock.


The addition of the black ceramic “Cerachrom” bezel is the most noticeable difference between the two models. This new and improved fixed bezel is highly scratch-resistant, corrosion-resistant, and resistant to the color fading effects of UV rays. When compared to its predecessor’s polished stainless-steel bezel, the new black bezel gives the impression that the dial is larger. Several aspects of the bezel design have also changed.

The typography used on the engraved tachymeter scale, in particular, is bolder and more legible, and it is filled with a platinum PVD fill. Another subtle difference on the bezel is the use of triangles rather than dots beneath the tachymeter numerals. The tachymeter numerals now rotate around the bezel rather than being displayed horizontally as they were on the previous model. 


Rolex’s Daytona watches, which feature their magnetic-resistant blue ‘Parachrom’ hairspring and stop-seconds for precise time setting, are powered by their in-house caliber 4130 self-winding movements. The 4130 caliber is an automatic chronograph movement that uses your kinetic energy to tighten the mainspring via a rotor. If you don’t move much during the day, the winding crown can be used to manually tighten the spring. On a full wind, the power reserve should allow the watch to run for approximately 72 hours, or 66 hours if the chronograph function is activated.

The Caliber 4130 movement is also COSC certified, which means it has a renowned Chronometer designation attesting to its dependability and high precision with a maximum deviation of -4/+6 seconds per day.


The Rolex Oyster bracelet is made of three pieces of oyster steel links. The two outer links are brushed, while the center link is beautifully polished. The links at either end of the bracelet are linked to the polished lugs on the case, so that when you look at it, the finishing alternates between polished, brushed, and polished for the center link.


The oysterlock double-locking folding clasp features Rolex’s proprietary Easylink 5mm extension link, which allows for a quick 5mm micro-adjustment to the bracelet’s size. This is a very useful feature that does not necessitate the use of any special tools to configure. This component was created to allow your watch to make up the difference in size for the natural expansion and contraction of the wrist caused by temperature and humidity variances.


From the start, the demand for this watch was out of this world. This, like all Rolex sport models, is built to last. It has excellent accuracy and enough water resistance that if it gets wet while swimming, snorkelling, or showering, you won’t have to worry. The Rolex brand is the most recognized watch brand in the world, so you’d get a lot of compliments and attention if you wore one of these.

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