love of fine mechanics is what drives the BPM Group (Bornhauser Performance Moteurs). Patrick Bornhauser, founding president of the motor distribution group, has always been fascinated by the multidisciplinary nature of the mechanical world. He had the idea of creating the Pecqueur Motorists Club to build bridges between the different worlds of car, motorbike, boat and aviation enthusiasts.

Patrick Bornhauser is the great-grandson of a master watchmaker, whose job it was to look after the town clock of St-Gallen in Switzerland, and he has always taken a keen interest in haute horlogerie. One day, by chance, he discovered that the differential mechanism used in cars was patented in 1827 by a talented watchmaker, Onésiphore Pecqueur. That was what led Patrick Bornhauser to look into developing an haute horlogerie timepiece whose Dual Time GMT complication would pay tribute to the inventor Onésiphore Pecqueur. This watch would grant access to the Pecqueur Motorists Club.

“In every Pecqueur Motorists collection to come, there will always be a differential. We will endeavour to showcase it through new complications that we are developing with our partner, LTM – Le Temps Manufacture,” explains Hamdi Chatti, the veteran watch industry professional who is overseeing the watchmaking side of the Pecqueur Motorists project.

How can a differential play a key role in developing a new watch?

Dial with seven depth levels

Imagine, if you will, that you have the first prototype of the Pecqueur Motorists watch in your hands. Your eyes are immediately drawn to the bridge at 7 o’clock. This unusual piece, whose sleek lines are reminiscent of the Eiffel Tower, protrudes onto the dial. At the top end, two rubies signal the presence of two toothed wheels, the larger of which frames a view into the heart of the movement, between its spokes.

The stepped architecture of the dial highlights the interplay of overlapping surfaces, where each layer is its own disc. As Christophe Beuchat of the Comblémine dial maker, who created the dial of the Pecqueur Motorists watch, explains: “The dial design is complex, with its different levels and varied textures. It is made up of seven pieces, requiring the addition of 2.5mm-tall ‘feet’ [immediately under the dial, to attach the dial to the movement]. These are relatively high, and quite rare in the industry.” It was a significant challenge, and one that Comblémine, which has been located in the Val-de-Travers since 2014, overcame with perseverance and ingenuity.

A close inspection of the case also exercises the imagination. Try to prolong the lines of the case surround that encloses the watch’s round face, and you’ll end up with a shape that’s almost an ellipse. That’s no coincidence, because the first elliptical compass was invented by a young Onésiphore Pecqueur around 1810. This is just one subtle nod by Stellantis Design Studio to the genius inventor. Aurélien Bouchet, head of AB Concept, which assembled the case of the Pecqueur Motorists watch, readily acknowledges this historical influence. “The Pecqueur project conveys a genuine sense of history through a piece of mechanical art. Being fascinated by this world myself, I was incredibly motivated to get involved in this magnificent adventure.”

The designers have maximised the interplay of light effects across the dial, incorporating a variety of finishes including Geneva stripes (a prominent visual signal), sandblasting and diamond-polishing. Expert artisans complete the effect with brushed, polished and satin surfaces on the case. The discreet three-part signature “Différentiel – Swiss Made – Onésiphore Pecqueur” and the circular logo bring a final elegant touch to the watch.

Squaring the circle

“The designers from Stellantis Design Studio drew inspiration from the wheels of a watch movement,” notes Hamdi Chatti. “The case and dial were designed with the help of compasses. The perfect harmony of these different circles, each fulfilling its own function, places the differential in the spotlight.” The result is visually stunning: three off-centre auxiliary dials and two windows nest together like interlocking gears, subverting all the traditional stylistic codes. But what, in fact, do these displays show?

The main dial at 11 o’clock indicates hours and minutes, as expected. A semicircular aperture at 1 o’clock reveals a number (identified by a white triangle) that can be selected via the upper pushpiece on the left of the case. Each number from 0 to 12 corresponds to a time zone, with daylight hours against a light grey background, and nighttime on dark blue. The hours and minutes on the auxiliary dial at 4 o’clock correspond to a different time zone, which can be set as follows: once the hour has been selected with the upper left pushpiece, the lower left pushpiece can be activated to automatically synchronise the time of the second time zone. The small disc inset into the auxiliary dial provides day/night confirmation. Seconds are shown on a small subdial at 6 o’clock.

FEATURES OF THE PECQUEUR DIFFERENTIAL

• The Differential of the Pecqueur LTM 5021 calibre allows the local time, 2nd time zone and day/night display to be adjusted either independently or synchronously.

• Local time and the time at destination (2nd time zone) are on two separate displays. The destination dial also has a minutes hand.

• A GMT disc shows the time zone for the time at destination.

• The operation of the spherical Differential mechanism is visible on the dial.

• A day/night indicator linked to the 2nd time zone shows whether the displayed time is between 6 am and 6 pm, or 6 pm to 6 am.

• Once the watch has been calibrated, one press of the pushpiece at 8 o’clock will adjust the GMT disc and set the time zone simultaneously.

• Ergonomic correction: when the 2nd time zone is being set, the Differential activates a planetary mechanism that accelerates the rotation of the GMT mechanism, allowing the second time zone to be set without affecting the operation of the main disc.

• A corrector at 10 o’clock adjusts the disc in relation to the 2nd time zone. Two corrections are possible: the 10 o’clock pushpiece adjusts only the GMT disc, while the 8 o’clock pushpiece adjusts both the GMT disc and the GMT time.

• 10 moving parts are mounted on 20 jewels: 1 disc for local time; 1 disc for the 2nd time zone display; 5 (including the differential) between the movement and the 2nd time zone display; and 2 for the seconds indicator.

Applied genetics

The dial and case of the Pecqueur Motorists watch enclose an unusually complex calibre. Its design and construction were entrusted to the discreet but prestigious Le Temps Manufacture (LTM), located in Fleurier in the Val-de-Travers, and founded in 2008 by entrepreneur Sylvain Jacques. The spec sheet of the Pecqueur Differential Dual Time LTM 5021 calibre speaks volumes. The stepped gears and sweeping lines of the differential reveal the DNA it shares with the patent registered by Onésiphore Pecqueur in 1827. By faithfully deconstructing the technical discoveries of a bygone age, LTM’s engineers are laying claim to a pedigree.

The LTM differential consists of a central element in the shape of a cross, framed by two large horizontal wheels known to watchmakers as “mobiles”. On either side of the central mechanism, two smaller vertical pinions screwed to the central plate make up the horizontal arms of the cross. “The major advantage of the differential is that it doesn’t interfere with the watch’s operation when the time zone is adjusted. That means greater precision,” Hamdi Chatti explains. In other words, the Pecqueur Differential Dual Time LTM 5021 calibre continues to beat at 28,800 vibrations per hour, or four “ticks” per second, even when the pushers are in operation. The balance and spring assembly thus retains its isochronism throughout the movement’s 60-hour power reserve. The movement’s aesthetic appeal belies the fact that it is made up of 237 components, contained in a depth of just 7.73 mm and a fitting diameter of 37.8 mm (16¾ lignes). Truly a remarkable achievement.

Pecqueur Motorists Club

The Pecqueur Motorists watch is intended for enthusiasts of the mechanical arts, many of whom will not yet have access to the rarefied circles of haute horlogerie. They will appreciate the technical ingenuity that goes into incorporating a differential that is genetically faithful to the spirit of its inventor, and the complex tiered architecture with its multiple displays, arranged around three off-centre auxiliary dials and two windows.

The emblem of the Pecqueur Motorists Club is an avant-garde timepiece with a minimalist aesthetic; a distinguished sports watch that reveals its pedigree with the utmost discretion. It is the mark of the exclusive “Bespoke Motoring Lifestyle” approach, as conceived by Patrick Bornhauser.

PACE (Pecqueur Art Craft Engineering): The Pecqueur Motorists Workshop

Produced in a limited series of 25, the “First Edition” collection of the Pecqueur Motorists watch is both impossible to categorise, and universal. Throughout the months of meetings and research, it has never failed to surprise us and pique our curiosity. It will doubtless emerge as one of the mechanical revelations of spring 2023. This watch shows that haute horlogerie can give rise to innovative projects, for which historical legitimacy provides the soundest of foundations.

To find out more about the Pecqueur Motorists Club, and the watch that grants entry, visit www.pecqueurmotorists.com