Tudor · Black Bay One

Strap for Black Bay 36 S&G / Champagne / Bracelet

Takes 19 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width19 mm
Case diameter36 mm
Reference79643-0005 (aka: M79643-0005)
FamilyBlack Bay One
MovementTudor caliber MT5400 Hours, Minutes, Seconds | Chronometer
CaseYellow Gold, Stainless Steel

Spring bar

Spring bars for Tudor

The right category for this model · choose the 19 mm size

The Black Bay One 79643-0005 (aka: M79643-0005), seen from the bench

The Tudor Black Bay One 79643-0005 is a 36 mm hybrid steel and yellow gold watch featuring the in-house MT5400 chronometer-certified movement beating at 28,800 vph with approximately 70 hours power reserve. The black dial features applied gold indices and gold sword hands. The lug width is 19 mm, characteristic of the Black Bay One family, ensuring proper proportions with the 36 mm case diameter derived from 1960s–1970s vintage models.

Frequently asked questions

What is the lug width of the Tudor Black Bay One 79643-0005?

The lug width of the Tudor Black Bay One 79643-0005 is 19 mm. This measurement represents the distance between the two metal attachment points (spring bars) of the case. It is an intentional design specification that maintains the correct visual proportions with the 36 mm case.

What is the best strap for the Tudor Black Bay One 79643-0005?

The best strap depends on your intended use and personal preference. Alligator leather in black or dark brown offers elegance and comfort; calf with vertical grain maintains versatility; vegetable-tanned leather develops a beautiful patina over time. For sport wear, canvas NATO is a thoughtful choice that emphasises the watch's tool-instrument character.

How do you change the strap on a Tudor Black Bay One?

Strap changing is straightforward: use a spring bar tool (included or available separately) to gently press the metal pins from the sides of the case. Once released, the old strap detaches easily. Insert the new strap into the lugs and reposition the pins until they click. No movement disassembly required.

Which aftermarket strap is compatible with the 79643-0005?

Any strap with a 19 mm lug width is compatible. On milanostraps.it you will find a selection of handcrafted straps in alligator, calf, vegetable-tanned leather, canvas and NATO, customisable for length, stitching and initials. Compatibility is guaranteed by lug width measurement.

How long does a leather strap last on the Tudor Black Bay One?

Durability depends on material and usage. Quality alligator lasts 5–8 years with ordinary maintenance (occasional leather cleaning). Calf leather lasts 3–6 years. Vegetable-tanned leather evolves continuously without real wear, maintaining function for 10+ years. Casati Milano straps come with an 18-month guarantee and can be refurbished.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

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Casati Milano · Via XX Settembre 15, Milan · by appointment only