Review of Tudor Black Bay Chrono 39 'Bumblebee'

The Geneva-based company Tudor introduced its long-awaited compact version of the chronograph in mid-2026.

This review examines the first modern Tudor Black Bay Chrono model with a diameter of 39 mm, reference M79310N-0001, known as the 'Bumblebee'. Although it's not an entirely new line, the Black Bay Chrono 39 offers a reduced and more compact version of the classic Black Bay Chrono with a 41 mm case.

Other versions of the Black Bay Chrono 39 will appear in the future, but the first model features a black and yellow dial, becoming part of the 'Daring Colors' series, which includes variants with pink and light blue dials of the standard model. The 41 mm and 39 mm models have different characters and suit different preferences and wrist anatomies.

Comparison of Tudor Black Bay Chrono 39 and Rolex Daytona: features of mechanisms and design

In the Tudor Black Bay Chrono 39 review, I emphasize the need for comparison with other chronographs, especially given that Tudor and Rolex are part of the same group. There are only two main chronograph mechanisms produced between them (excluding the Rolex Yacht-Master II countdown timer). The Rolex Cosmograph Daytona, equipped with caliber 4131, is extremely popular.

Both Tudor Black Bay Chrono models use the in-house automatic chronograph MT5813. The original Black Bay Chrono was not intended to compete directly with the Daytona due to differences in proportions and character. On paper, the 40 mm Rolex Daytona and 41 mm Tudor Black Bay Chrono look similar, but on the wrist, they feel different: the Daytona is 11.9 mm thick, while the Black Bay Chrono 41 is 14.4 mm. Additionally, the Daytona costs about three times more than the Tudor Black Bay Chrono (assuming it can be purchased at retail price). Therefore, the market has long awaited a classic Swiss Tudor chronograph at an affordable price but with proportions close to the Rolex Daytona. The Black Bay Chrono 39 fills this niche.

Case and design of Tudor Black Bay Chrono 39: how size was reduced without sacrificing functionality

The Tudor Black Bay Chrono 39 case is made of 316L stainless steel with predominantly matte finish and some polished elements. The diameter is 39 mm, the thickness is 13.1 mm, and the lug-to-lug distance is 47 mm. Water resistance reaches 200 meters, and the dial is protected by a box-style sapphire crystal. The crown and chronograph pushers have screw-down fixtures (the pushers are mainly for aesthetic purposes). The bezel with a tachymetric scale is made of black anodized aluminum with engraved markings.

Tudor completely redesigned the case and bracelet for the reduced 39 mm version. The model became 2 mm narrower and 1.3 mm thinner compared to the 41 mm version. Design techniques helped visually reduce the size: a slightly recessed bracelet in the lugs and more massive polished edges of the case create the impression of less thickness and compactness.

Technical features of the MT5813 mechanism and challenges in reducing the case

Reducing the thickness of the case was a challenging task since Tudor did not create a new mechanism for the Black Bay Chrono 39. It is based on the same automatic chronograph MT5813 with a thickness of 7.23 mm, using the Breitling B01 architecture, which by definition is not thin. Thick chronographs provide functions such as a column wheel and vertical clutch - all of which are present in the MT5813. Additionally, such mechanisms are usually more reliable due to the greater space between moving parts, reducing the risk of breakdowns.

However, many prefer to wear thinner watches, and creating thin chronographs is costly and complex. In this context, Tudor's success is not just in reducing size, but in creating a compact case around a thick mechanism.

The MT5813 caliber operates at a frequency of 4 Hz and provides a power reserve of up to 70 hours. Features include time display, a 45-minute chronograph counter (a rare option), and a date displayed in a window at the '6 o'clock' position. An important feature is the use of a silicon balance spring - this enhances timekeeping stability (isochronism) and protects the mechanism from the influence of temperature and magnetic fields, which can impair accuracy. While the MT5813 does not claim the precision of the Rolex 4131 caliber, it boasts high performance and is certified as a COSC chronometer, also undergoing Tudor's internal tests with an accuracy of -2/+4 seconds per day.

Bracelet and wearing comfort of Tudor Black Bay Chrono 39

Unlike the Black Bay Chrono 41 model, the Black Bay Chrono 39 bracelet is equipped with the Tudor T-fit micro-adjustment system for smooth length adjustments. This feature is likely to be implemented in other Black Bay models. The new three-link bracelet tapers towards the clasp and provides high wearing comfort. Not everyone may like the integration of the end links with the case, but a tighter fit would make the watch visually thicker and less elegant. Personally, I prefer the Oyster-style bracelet design over the multi-link Jubilee typically used in the 41 mm version. Additionally, the Black Bay Chrono 39 bracelet differs from the 41 mm model's bracelet with a more pronounced taper and the absence of side rivets, which not everyone appreciates.

Dial 'Bumblebee': style and readability

The black and yellow dial of the 'Bumblebee' model looks bright and sporty, but may not suit everyone due to its expressiveness and specific style. Tudor plans to release additional dial variants for the M79310N model in the future. A large amount of SuperLumiNova luminescent coating ensures excellent readability in the dark. The signature 'snowflake' on the hour hand matches the Submariner-style markers. The watch looks modern and harmoniously fits into Tudor's conservative range. While I hope for the expansion of Tudor's chronograph collection, the Black Bay Chrono 39 is an excellent choice for those looking for a high-performance chronograph in a more compact case.

Conclusion and price of Tudor Black Bay Chrono 39 'Bumblebee'

For Tudor watch enthusiasts looking for a Swiss chronograph with a powerful mechanism in a convenient case, the Black Bay Chrono 39 will be a significant addition to the collection. The model features a comfortable fit, successful proportions, and an attractive price-to-quality ratio compared to counterparts from other brands. The recommended retail price of the Tudor Black Bay Chrono 39 'Bumblebee' (reference M79310N) is $6,725.

Key features of Tudor Black Bay Chrono 39 'Bumblebee':