Seiko Prospex Speedtimer Automatic x Datsun 240Z black dial leather strap 39,5 mm

Heritage & The Speedtimer x Datsun Collection

In 1969, Japan saw the birth of two creations destined to become legends: on one side, the Seiko Speedtimer, the world’s first automatic chronograph equipped with a vertical clutch and a column wheel—a true technical milestone that shaped the history of watchmaking. On the other, the Datsun 240Z, a sleek sports coupé that revolutionized the automotive market with its unbeatable price-to-performance ratio, winning over both Japanese drivers and North American enthusiasts.

At first, these two icons had nothing in common beyond their homeland and pioneering spirit. Yet, their paths dramatically crossed in 1971 during the grueling East African Safari Rally. This race, considered the toughest in the world, forced cars and drivers to endure over 6,200 kilometers of brutal terrain. The number 11 Datsun 240Z, proudly sponsored by Seiko, emerged victorious against prestigious rivals. Inside the cockpit, co-pilot Hans Schuller wore a Seiko Speedtimer 6139, cementing the bond between two worlds that few would have thought connected: precision watchmaking and motorsport.

That victory was more than a sporting success—it embodied a shared philosophy of uniting reliability, durability, and innovation in the pursuit of performance. Both Datsun and Seiko were committed to making advanced technology accessible while ensuring uncompromising toughness.

More than half a century later, Seiko pays tribute to this memorable chapter with a limited-edition Datsun trilogy. Three models celebrate this dual heritage: the SPB517, a mechanical three-hander with an internal countdown bezel; the SRQ057, a high-end automatic chronograph powered by the 8R48 caliber; and the SSC957, a modern solar-powered chronograph. Each piece represents a facet of this historic partnership, but the SPB517 holds a unique position. Produced in 2,500 numbered units, it offers a more refined, understated take on the Speedtimer, retaining its racing spirit but in a compact, elegant three-hand + date format.

This limited edition is not just nostalgic homage—it proves that the spirit of the 1970s can be intelligently reimagined for today. With the SPB517, Seiko delivers a watch that draws from its racing DNA while remaining perfectly suited for everyday use, seamlessly bridging past and present.

Design & Aesthetics

The Seiko Prospex Speedtimer SPB517 impresses immediately with its balance between racing spirit and contemporary elegance. Its stainless steel case measures 39.5mm in diameter and just 12mm thick, reviving the sharp, faceted lines of 1970s Speedtimers but with modernized proportions for comfort and versatility. Compact yet robust, with 200 meters of water resistance, it is as much a tool watch as it is an everyday companion. Alternating brushed and polished surfaces add refinement, revealing subtle light play that reinforces its premium feel.

The dial, in deep anthracite gray with red and black accents, draws directly from the aesthetics of the Datsun 240Z. This discreet yet evocative color palette echoes the livery of the Safari Rally–winning car of 1971. Applied indices with luminous pips ensure readability even in darkness, while faceted hands coated in Lumibrite guarantee sharp legibility in all conditions—true to the model’s utilitarian intent.

The central seconds hand, slim and dynamic, is accented with red, recalling the dashboard instruments of a race car. At 4:30, the date window integrates discreetly into the dial, preserving visual balance. But the defining feature of the SPB517 is its internal rotating countdown bezel. Operated via a secondary crown at 4 o’clock, it features a retro-styled numeral scale inspired by racing instruments. Functional and intuitive, it allows the wearer to time short intervals, whether for race starts or everyday tasks.

A curved sapphire crystal with inner anti-reflective coating protects the watch, adding depth to the dial and ensuring excellent clarity. The screw-down caseback is engraved with the historic Datsun logo, emphasizing the exclusive character of this edition.

The SPB517 is delivered on a perforated black leather strap, directly inspired by the driving gloves of 1970s racers. With its red lining, it reinforces the motorsport connection while adding a distinctive visual flair. A push-button deployant clasp provides both comfort and security for daily wear.

Movement

At the heart of the SPB517 is the automatic 6R55 caliber, a modern in-house movement developed by Seiko. It represents a significant upgrade over earlier 6R35 and 4R-series calibers, delivering an extended 72-hour power reserve—three full days. This generous autonomy means the watch can be left aside for an entire weekend and still be running come Monday, a convenience appreciated by collectors and daily wearers alike.

The 6R55 beats at 21,600 vibrations per hour (3 Hz) and is equipped with 24 jewels. It offers hacking seconds for precise time-setting, as well as manual winding in addition to automatic winding via the rotor.

Seiko specifies an accuracy range of –15 to +25 seconds per day, though many users report more stable real-world performance, reinforcing the caliber’s reputation for reliability and robustness. It also offers magnetic resistance of 4,800 A/m, a practical advantage in today’s environment full of electronic devices.

Durable and easy to service, this movement reflects the Prospex philosophy: professional-grade specifications paired with everyday accessibility. By equipping the SPB517 with the 6R55, Seiko ensures the perfect balance of mechanical performance, daily dependability, and authentic horological heritage.

A Limited Edition of 2,500 Pieces

The SPB517 belongs to an exclusive trilogy created by Seiko to celebrate its shared legacy with Datsun and the iconic 240Z. Limited to just 2,500 pieces worldwide, it stands out in the Speedtimer range as both a historic homage and a contemporary sports watch.

Each unit is individually numbered and distinguished by a caseback engraved with the Datsun logo, recalling the partnership that led to the 240Z’s legendary victory in the 1971 Safari Rally. This detail imbues the watch with narrative depth—it is not just a timepiece, but a fragment of motorsport and watchmaking history.

Positioned at an accessible price considering its exclusivity and technical features, the SPB517 appeals equally to Seiko enthusiasts and classic car aficionados. Its subtle aesthetic, blending vintage cues with modern practicality (200m water resistance, countdown bezel, 72h power reserve), makes it a versatile daily wearer with symbolic weight.

It perfectly embodies the Prospex philosophy—Professional Specifications—but with an added emotional dimension: a tribute to the historic alliance of two Japanese icons born in 1969.