De Bethune DB28 Steel Wheels Sapphire Tourbillon

During the Geneva Watch Days event in August 2020, Swiss luxury watch brand De Bethune unveiled the iconic DB28 Steel Wheels watch for the first time equipped with a tourbillon. The movement’s delta bridge and two barrel covers are made of sapphire crystal.

A limited edition of only 10 pieces, the DB28 Steel Wheels Sapphire Tourbillon celebrates the 10th anniversary of the DB28 collection. It pays tribute to the iconic watch family by ably perpetuating the heritage of its predecessors: perfect balance, contemporary and bold aesthetics at the service of exceptional mechanics.

When the first DB28 was launched in 2010, De Bethune’s idea was to present a timepiece with an identity of its own and a resolutely futuristic vision of the art of watchmaking. The design naturally follows through in the spirit of the Manufacture’s creations. The distinctive shape of the case and the crown at 12 o’clock, inspired by pocket watches, are characteristic features of the contemporary aestheticism specific to De Bethune.

It is on this timepiece that the patent for De Bethune’s unique, innovative floating lugs, designed to significantly improve comfort, acquired its full meaning. Since then, the DB28 – named Best Watch of the Year and awarded the Aiguille d’Or prize at the Grand Prix d’Horlogerie de Genève (GPHG) in 2011 – has never ceased to express past, present and future watchmaking culture through different variants.

Following through on a series of contemporary iterations, from Skybridge to the Kind-of-Blue, by way of the more recent DB28XP, DB28XP Starry Sky and DB28XP Tourbillon, De Bethune has time and again found a new way to reveal new facets of this design, already instantly recognizable by its sleek and taut lines.

The DB28 Steel Wheels was introduced in 2018, under the sign of transparency and light, with the idea of opening the dial to reveal the contemporary architecture of its movement.

Recognizable by its delta shaped bridge – a De Bethune hallmark – and its moon at 6 o’clock, the DB28 Steel Wheels fascinates with a multitude of different forms – hemispherical, concave, and spherical – for an architecturally dynamic result. It is all about levels of perception, layers and reliefs, light playing with shadows and reflections. Cut from titanium, light on the wrist, this watch reveals a contemporary, architectural fusion of space, time and light.

The DB28 Steel Wheels Sapphire Tourbillon

Most often used in the production of watch cases, sapphire crystal takes on a new role for De Bethune. Here, it finds a new vocation in the form of the signature delta-shaped bridge and the cover for each of the two barrels. Blue for the bridge, clear for the barrel covers, these elements are integrated into the movement, letting light in to play and offer new reflections – and allow the eyes to literally plunge into the mechanism.

De Bethune DB28 Steel Wheels Sapphire Tourbillon

The transparency of these sapphire crystal components not only magnifies the movement, but also offers a different kind of lighting, new brilliance and shimmering, that highlights the taut lines, the architecture and the different levels of the caliber for an intriguing sense of depth.

Each sapphire crystal component is encircled in polished titanium. Always in the spirit of taking things further, as far as possible, Denis Flageollet designed the sapphire glass components, cutting them by laser with utmost precision so they fit in perfectly with the forms, rises, angles, the teeth – the bridge as well as the barrel covers – all perfectly adjusted like lace of sapphire crystal.

To this is added a ring of polished titanium to circle each barrel cover. The sight of the delta bridge and two barrel covers in sapphire crystal is something never seen before, along with the cut of the glass, underscored on its periphery by the polished metallic grey line, accentuating a resolutely contemporary aesthetic.

De Bethune DB28 Steel Wheels Sapphire Tourbillon

The thicknesses of the sapphire crystal vary according to the components. The sapphire of the bridge is 1 mm thick to ensure functional rigidity, whilst the sapphire of the barrel covers is 0.3 mm thick. These glass components in no way compromise robustness or, of course, reliability when worn – solid, perfect resistant to small everyday shocks is assured.

De Bethune has always crafted its watch hands in-house, by hand, in the workshop in l’Auberson. The DB28 Steel Wheels Sapphire Tourbillon thus comes with a particularly finely worked hour hand. It consists of 4 distinct elements: the barrel made of steel for technical reasons, a titanium insert, an inner component of matt titanium, and a polished titanium outer component. Each component is worked differently. The result is unique. At the back, the power reserve indication can be read with a hand-blued steel hand, also made, as is the custom, by hand in De Bethune’s workshop.

In the vast array of complications and functions, of horological disciplines in which De Bethune has become a virtuoso, the tourbillon often played a leading role. The DB28 Steel Wheels boasts a tourbillon featuring an extraordinarily lightweight cage (0.18 grams, the lightest ever created). Rotating on itself every thirty seconds, it comprises a total of 63 components (the lightest of which weighs less than 0.0001 grams!).

Nowadays, a wristwatch is subjected to more action than may be safely and sufficiently compensated for. Changes in position are often abrupt and sometimes chaotic. Indeed, the kinetic forces inflicted on a mechanical watchmaking movement under normal wear conditions might seem quite staggering. Just as Breguet had invented the tourbillon to meet the constraints of marine watches, De Bethune designed a tourbillon for the new dynamics of wristwatches.

To compensate for the sheer force of wrist movements, the tourbillon cage must be as light as possible and operate at maximum frequency and speed of rotation, all with weight and inertia at absolute minimums.

The tourbillon is a titanium and silicon creation that beats at a frequency of 36,000 vibrations per hour. It features an extraordinarily lightweight cage (0.18 g, the lightest ever) that rotates on itself every thirty seconds and comprises 63 components (the lightest of which weighs less than 0.0001 g). These special qualities let the De Bethune’s tourbillon to simply fulfill its function more ably for today’s watches. The futuristic shape of the Tourbillon Bridge holds the tourbillon perfectly in position, symmetrically, from both sides.

Among the various hand-made decorations specific to De Bethune’s movements, the mirror-polishing of the titanium pieces offers an astonishing play with light. The surfaces of the components are finished to perfectly reflect ambient light. The metal surface is patiently polished until it becomes a true mirror.

And unparalleled comfort thanks to its floating lugs, kept to an intermediate size on this watch.

De Bethune DB28 Steel Wheels Sapphire Tourbillon

The DB28 Steel Wheelss Sapphire Tourbillon features a polished grade 5 titanium case, mounted on the new floating lugs unveiled this year. Entirely redesigned, harmonized and adapted to the spirit of the watch, they are tipped by the famous ‘bullets,’ more prominent here, reminiscent of the spirit of the first De Bethune collections.

The alligator strap with a titanium buckle contributes to the practicality and everyday wearability of this very special timepiece.

Technical details

Model: DB28 Steel Wheels Sapphire Tourbillon
Reference: DB28SWTTIS1

Functions
Hours, Minutes, 30’’ indicator via the ultra-light De Bethune tourbillon cage at 6 o’clock, Power reserve situated on the back

Movement
DB2019V5
Mechanical hand-wound movement
Adjustment: Winding and setting the time by means of the crown (2 positions)
Number of parts: 272
Jewelling: 39 jewels
Diameter: 30 mm
Power reserve: 5 days, ensured by a self-regulating twin barrel – De Bethune Innovation (2004)

Titanium balance wheel with white gold inserts, optimised for temperature differences and air penetration – De Bethune Patent (2016)
“De Bethune” balance-spring with flat terminal curve – De Bethune Patent (2006)
Silicon escape wheel
Ultra-light De Bethune 30’’ tourbillon in titanium – De Bethune Innovation (2008)
Frequency: 36,000 vibrations per hour
Adornment: Motion works bridge and concave cover plate in grade 5 titanium, mirror-polished
Curved, open worked and beveled barrel bridge with glass blued sapphire
Open worked and hand sailed barrels with glass blued sapphire and blued titanium beveled rings
Rhodium power reserve indicator background decorated with “De
Bethune” circular graining
Blued and engraved ring
Steel parts beveled and polished by hand

Display
Display: Minutes and hours hand in hand-polished sand-blasted blued titanium
Ultra-light De Bethune 30’’ tourbillon in titanium – De Bethune Innovation (2008)

Dial
Circular-grained titanium hours ring
Spherical polished titanium hour-markers set and 30” dial on a blued polished titanium circle

Case
Material: Polished grade 5 titanium
Diameter: 43 mm
Thickness: 9.80 mm
Lugs: Polished grade 5 titanium floating lugs – De Bethune Patent (2006)
Crystal: In sapphire crystal (1800 Vickers hardness) with double anti-reflective coating
Case back: Screwed case back in grade 5 polished titanium that opens on a linear power reserve indicator in blued steel Sapphire crystal (1800 Vickers hardness) with double anti-reflective coating
Water resistance: 3 ATM

Strap
Extra-supple alligator leather, alligator lining
Buckle: Pin buckle in polished grade 5 titanium