The Evolution of the 'Big Block'
For decades, the Tudor chronograph lived in the shadow of its larger-than-life sibling, the Rolex Daytona. However, in the late 1970s, Tudor carved out its own identity with the 'Big Block'—a chunky, unapologetic chronograph that introduced automatic winding to the Wilsdorf family before the Daytona did. The modern Black Bay Chrono line has always sought to channel that 'Big Block' energy, but the previous 41mm iterations often felt like they were wearing the user, rather than the other way around. The introduction of the Ref. 79310N, affectionately dubbed the 'Bumblebee' for its striking black and yellow-gold contrast, marks a pivotal shift in Tudor's design philosophy.
The 39mm Pivot: A Masterclass in Proportions
The headline here is the 39mm case. By shaving 2mm off the diameter, Tudor has fundamentally changed the geometry of the watch. When we talk about 'wearability' at Vivir, we aren't just talking about whether the lugs hang over the wrist. We are talking about the visual weight. The 39mm 'Bumblebee' feels concentrated. The 47mm lug-to-lug measurement is the 'sweet spot' for the modern collector, allowing the watch to sit flat against the radius bone, providing a stable platform for the chronograph pushers.
However, we must address the elephant in the room: the thickness. At 14.2mm, this is not a thin watch. Because Tudor utilizes a modular-adjacent architecture for the MT5813 (to maintain that 200m water resistance), the case retains a certain verticality. In my week of testing, this meant the watch occasionally struggled with the tightest of French cuffs. But for daily wear—paired with a cashmere sweater or a technical blazer—the height becomes an asset, providing a sense of 'rugged luxury' that is core to the Tudor brand identity.
The 'Bumblebee' Aesthetic: Steel, Gold, and Sophistication
The 'Bumblebee' nickname comes from the high-contrast color palette. The matte black dial is punctuated by champagne-colored, recessed sub-dials at 3 and 9 o'clock. The use of yellow gold for the fixed bezel (with its black aluminum tachymeter insert), the screw-down pushers, and the crown creates a visual warmth that prevents the watch from feeling like a cold piece of lab equipment. This is a watch that looks as good under the lights of a Soho dinner as it does in the cockpit of a vintage 911.
The legibility is generally excellent, thanks to the high-contrast gold hands against the black dial. However, the 'Snowflake' hour hand—a Tudor signature—remains a point of contention for chronograph purists. At 3:00 and 9:00, the wide diamond shape of the hand can momentarily obscure the sub-dials. In practice, this is a minor inconvenience, but if you are timing a critical three-minute espresso extraction, you might find yourself tilting your wrist to see past the hour hand.
The Engine: Calibre MT5813
The movement inside the 79310N is a triumph of industrial collaboration. Based on the Breitling B01, the MT5813 is enhanced by Tudor with a high-tech silicon hairspring and a proprietary finish. This is a column-wheel chronograph with a vertical clutch. What does that mean for you, the wearer? It means that when you press the top pusher, the chronograph hand starts with a smooth sweep, rather than the 'jump' associated with cheaper cam-actuated movements. The pusher feel is tactile and 'clicky,' requiring a deliberate force that prevents accidental starts.
The 70-hour power reserve is the 'weekend-proof' standard we expect. I took the watch off on Friday evening, and on Monday morning, it was still ticking with Swiss precision. For the young collector who rotates between a diver and a dress watch, this reliability is non-negotiable.
Daily Utility: The T-Fit Revolution
I cannot stress enough how much the T-fit clasp improves the daily experience. The 'Bumblebee' comes on a riveted S&G bracelet that tapers beautifully. In the past, Tudor's bracelets were criticized for lacking on-the-fly adjustment. The T-fit system solves this, offering five positions of tool-free adjustment. Throughout a day that included a morning commute, three hours of typing, and a post-work gym session, I adjusted the clasp three times. Each time, the watch went from 'slightly too tight' to 'perfect' in three seconds. This is the level of engineering that separates a luxury item from a mere accessory.
The Verdict
The Tudor Black Bay Chrono 39 'Bumblebee' Ref. 79310N is not just a downsized diver-chronograph; it is the most cohesive expression of Tudor’s modern identity. It is flashy without being gaudy, heavy without being cumbersome, and technically superior to almost anything else in its price bracket. If you have been waiting for the Black Bay Chrono to grow up (by shrinking down), your wait is over. This is the daily wearer for the collector who values substance as much as style.
