Tudor's been making the Black Bay Chrono at 41mm since 2017. Collectors have been asking for a smaller case almost as long. On June 5, 2026, Tudor answered: the Black Bay Chrono 39 "Bumblebee," ref. M79310N-0001, at $6,725.
The yellow dial is what everyone is talking about. The 39mm case is what matters.
Images in this post are AI-generated for editorial illustration. They may not represent the exact watch configuration. For accurate product photography, visit tudorwatch.com.
Tudor Black Bay Chrono 39 Bumblebee ref. M79310N-0001, $6,725 retail. AI-generated editorial image.
The Size Reduction Is the Actual News
Two millimeters does not sound like much. On a chronograph with push-pieces and a tachymeter bezel, it changes the entire wear experience.
The original Black Bay Chrono 41mm measures 14.4mm thick. The new 39mm version comes in at 13.1mm — 1.3mm slimmer — with a lug-to-lug of 47mm. That is a meaningful shift for anyone who has tried the 41mm and felt it stack too high under a cuff.
Tudor achieved the size reduction without swapping the movement, which is the impressive part. The same Calibre MT5813 — the COSC-certified column-wheel vertical-clutch chronograph developed in partnership with Breitling — sits inside both cases. 28,800 vph, 70-hour power reserve, silicon balance spring. Nothing was compromised to get there.
The 39mm case is 1.3mm slimmer and noticeably more wearable under a cuff than the 41mm. AI-generated editorial image.
What Tudor Changed, and What They Didn't
The case flanks are more domed than the 41mm version, making the sides appear thinner at a glance. The crown geometry was updated — slightly more traditional in shape than the 41mm, which divided opinion. The caseback is more rounded.
The bracelet drops the riveted three-link construction of some earlier variants: the Bumblebee ships on a full satin-brushed three-link steel bracelet with no rivets, closed by Tudor's T-fit micro-adjust clasp. Clean.
What did not change: 200m water resistance, screw-down crown and pushers, sapphire crystal with anti-reflective coating. The specification sheet is intact.
The Yellow Dial: Feature or Bug?
The "Bumblebee" colorway — yellow main dial, black bicompax sub-dials at 3 and 9 o'clock, snailed sub-dial texture — is part of Tudor's Daring Watches collection alongside the Flamingo Blue and Pink chronographs released on the 41mm in recent years.
Yellow chronograph dials have a real motorsport lineage. Heuer used them. Breitling used them. The contrast between yellow and black is genuinely high-legibility. This is not a novelty color for its own sake.
The honest take: it is an acquired taste, and it will not suit every buyer. The Daring designation signals limited availability — not strictly limited edition, but not open shelf stock either. Demand for the yellow specifically will be patchy across markets.
That patchiness is a buying signal. If the yellow is not for you, wait: panda and reverse-panda colorways on the 39mm format are the obvious next releases, as Monochrome notes in their review. If it is for you, this is available now.
The Bumblebee on wrist. The 39mm format is the real story for buyers who found the 41mm too large. AI-generated editorial image.
How It Stacks Against the 41mm Pre-Owned Market
The 41mm Black Bay Chrono in panda configuration trades around $4,800–$5,200 pre-owned on Chrono24 as of June 2026. That is a meaningful discount off $6,800 retail.
The 39mm Bumblebee is brand new — no pre-owned market exists yet. At $6,725 retail it lands only slightly below the 41mm retail, so the value question is really about case size preference and whether you want the smaller format enough to pay new.
| Spec | Black Bay Chrono 39 | Black Bay Chrono 41 |
|---|---|---|
| Case diameter | 39mm | 41mm |
| Case thickness | 13.1mm | 14.4mm |
| Lug-to-lug | 47mm | 47mm |
| Movement | MT5813 | MT5813 |
| Power reserve | 70 hrs | 70 hrs |
| Water resistance | 200m | 200m |
| Price (new) | $6,725 | $6,800 |
39mm vs 41mm side by side. Same movement, same spec sheet, meaningfully different wearability. AI-generated editorial image.
The MT5813: Still One of the Best Movements at This Price
The Calibre MT5813 deserves its own section because it is routinely undersold.
The architecture derives from the Breitling B01 — one of the most respected in-house chronograph movements built. Tudor developed it in partnership with Kenissi, the movement manufacturer both brands co-own. The column wheel controls start/stop/reset. The vertical clutch eliminates the jump at chronograph start you get from lateral clutch designs. A LIGA-fabricated intermediate pinion with split elastic teeth eliminates backlash and keeps the chronograph seconds hand stable.
COSC certification means independently verified accuracy to -4/+6 seconds per day. Tudor holds its own assembled pieces to -2/+4 seconds — a tighter standard than the certificate requires.
At under $7,000, there is no better-specified chronograph movement on the market from a manufacture. Competitors at this price tier are either using ETA/Valjoux bases or paying a premium for the name over the engineering.
The Buy Case
For buyers who have been waiting for a 39mm BB Chrono: this is it. The yellow limits the audience, which means availability will be better than a panda version would be on launch day. If the color works for you, buy it now.
For buyers who want a 39mm but in a traditional colorway: wait 12–18 months. The panda and reverse-panda on 39mm are coming. They will trade at a pre-owned discount when they do.
For buyers on the 41mm pre-owned market: nothing changes. The Tudor Black Bay family guide at 5dwatches.com covers current pre-owned pricing across every reference — the 41mm Chrono remains strong value in the $4,800–$5,200 range.
The Bumblebee's motorsport color roots in context. AI-generated editorial image.
Browse pre-owned Tudor chronographs at 5dwatches.com/shop/tudor.