s Richard Mille enters the fifth year of its ongoing partnership with the luxury British supercar maker McLaren Automotive, the two brands reveal the result of their latest and most ambitious collaboration to date - the RM 40-01 Automatic Tourbillon McLaren Speedtail.

As the name suggests, this remarkable and unique watch honours the fastest, most advanced and most exotic road car McLaren has yet produced - the futuristic Speedtail.

Based on the form of a teardrop, the most aerodynamically efficient shape found in nature, the Speedtail is the apotheosis of the streamlined hypercar, a three-seat grand tourer that became the third car in McLaren’s Utimate line-up.

With its 1,070-horsepower hybrid powertrain, the Speedtail covers 112 metres per second when travelling at its top speed of 250mph/402kph, making it the fastest McLaren road car to date. McLaren’s relentless pursuit of aerodynamic efficiency provided the starting point for the design of the RM 40-01 Automatic Tourbillon McLaren Speedtail.

“There are many similarities between the way that Richard Mille and McLaren approach common design an engineering challenges, such as saving weight, reducing vibrational impact and minimising resistance,” said Rob Melville, McLaren Automotive’s design director, with the new RM 40-01 perfectly demonstrating why the two brands make ideal partners.

He continued: “When it came to the RM 40-01, we had considerable input in sharing the highlights of the car and the philosophy behind it. With the Speedtail, we set out to produce a car that had an artistic quality to it. That has certainly come through in the watch, which beautifully mirrors the many various details of the Speedtail in its finish, materials and its uncompromising design.”

It took Richard Mille’s casing department, led by Technical Director Julien Boillat, an unprecedented 2,800 hours spread over 18 months to perfect the lines. Like the Speedtail on which its based, the watch’s lines mimic the form of a water droplet while bezel indentations evoke the bonnet openings, and pushers that recall the air outlets behind the front wheels.

“As well as taking inspiration from the teardrop shape of the Speedtail, we also faced the challenge of seamlessly combining existing Richard Mille cues with those of McLaren,” explains Boillat. “The watch has one of the highest levels of finishing ever executed at Richard Mille. There has been a lot of development with our anglers and polishers. The attention to detail is extreme, with mirror polished, plain and satinised effects in different areas and the combined use of titanium and Carbon TPT^®. The case itself is made from 69 individual parts.”

Due to the unprecedented complexity of the design, five prototypes were created before the optimum shape was achieved. The challenge lay in the fact that the case is significantly wider at 12 o’clock than at 6 o’clock, with a further taper between the titanium bezel and case back, which are separated by a caseband made from Carbon TPT^® and unequal length titanium pillars.

To protect the RM 40-01’s state-of-the-art movement, Richard Mille developed a unique upper crystal glass featuring a ’triple contour’ to account for the decreasing taper and thickness of the bezel. It alone took 18 months to perfect.

The strap is also a unique design, being asymmetrical and with the rubber version using Vulcolor^® technology from Biwi SA, a special process that enables coloured rubber to be over-moulded - so allowing the iconic McLaren orange accent coloured stripe seen at 6 o’clock on the movement to extend to the wrist.

Despite the extraordinary anatomy of the case, Salvador Arbona, Richard Mille’s Movement Technical Director, created a horological ’engine’ that seamlessly occupies all the available space and introduces a level of mechanical sophistication that makes the RM 40-01 Automatic Tourbillon an appropriately extraordinary companion to the Speedtail.

Grade 5 titanium has been used for key components such as the bridges, the bridge screws, the baseplate and the rotor core. The CRMT4 calibre that drives the RM 40-01 introduces the first in-house development of a power reserve display as well as the oversize date and function selector complications. All of which are firsts at Richard Mille on an in-house tourbillon.

In the pursuit of perfection, three power reserve systems were developed before the definitive version was arrived at which is integrated into the watch. The entirely new movement architecture demanded a remarkable 8,600 hours of development, much of which went into finalising the extreme level of detail.

The complexity of the components, the multitude of details and, above all, the attention applied to the finishing place the RM 40-01 firmly at the peak of Swiss-made watches. The rims, for example, are buff-polished and the progressive angles - among other elements - and the bevellings are gradual hand-polished.

An often-forgotten detail, the finishing is applied not only to visible parts but also to parts that are hidden, such as the lower component surfaces. Some wheels are machined with a McLaren logo that adorns the bonnet of the Speedtail, while the domed parts usher in new surface profiles that were required to translate the car’s curves (which can be seen on the tourbillon bridge).

And in order to preserve the overall balance of the watch and its sleekness of line, the date corrector was positioned at 8 o’clock - a far more technically complex but also more aesthetically pleasing solution than the easier option of locating it at 11 o’clock.

The platinum and red gold winding rotor is inspired by the Speedtail’s bonnet and the barrel-setting by its roof line. The gentle, downward curve that the mechanism follows from 12 o’clock to 6 o’clock recalls the brushed metal divider between the car’s cockpit and its bodywork, a demarcation McLaren was inspired to incorporate because of the design of previous Richard Mille watches, while the orange line running from the lower part of the movement and on to the strap mimics the vertical stoplight mounted in the Speedtail’s rear screen.

To reflect the 106 McLaren Speedtails manufactured, 106 RM 40-01 Automatic Tourbillon McLaren Speedtail watches are planned.