The Black Bay 54 is the one that finally got the size right. 37mm across, a hair over 11mm thick, and a lug-to-lug of roughly 46mm — this is the modern Black Bay that actually wears like the 1950s diver it is pretending to be.
It is also the Black Bay where strap choice matters most, and there is a real reason for that which nobody ever mentions. I will get to it in a second.
First, the bit that stops you ordering the wrong thing.
Strap size and fit guide (read this before you buy anything)
Your Tudor Black Bay 54 (Ref. M79000N) has a 37mm case and a 20mm lug width.
If you have read somewhere online that the Black Bay 54 is 19mm, that is wrong. It gets repeated on a surprising number of strap sites, and it costs people an order. Tudor's own specification for this reference says 20mm, and every hands-on review that measured it agrees. Your 54 takes a 20mm strap. Full stop.
On Helvetus product pages, select "Black Bay 54" as the model option before you add to cart.
And here is the subtle one: the Black Bay 58 is also 20mm, but it is not the same selection. Because the widths match, people assume the two are interchangeable and pick whichever option they see first. The 54 has a different case — smaller, thinner, with a different lug profile — and our straps are cut to the case, not just to the width. Same number, different watch. Pick "Black Bay 54".
Checklist: 37mm case, 20mm lugs, select "Black Bay 54".
Why the strap does more work on the 54 than on any other Black Bay
Here is the thing nobody points out.
20mm of strap on a 37mm case is the widest strap-to-case ratio in the entire Black Bay range. Run the numbers: the Black Bay 41 is 22mm on a 41mm case. The BB58 is 20mm on 39mm. The 54 is 20mm on 37mm. Tudor kept the full 20mm width and shrank everything around it.
What that means in practice is that when you look down at your wrist, the strap makes up a bigger share of what you actually see than on any other watch in the family. On a BB41 the strap is an accessory to the watch. On the 54 it is closer to half the picture. Get the colour right and the watch looks intentional. Get it wrong and it is the first thing anyone notices.
The second reason is physical. Reviewers who have lived with the 54 keep making the same observation: the lugs do not turn down very much, so on smaller wrists the lug tips can sit slightly proud rather than following the curve. A bracelet cannot fix that — the first link has to clear the lug before it can bend. A soft rubber strap starts wrapping immediately. On this specific watch, that is a genuine comfort upgrade, not just a style change.
And for what it is worth: Tudor sells the Black Bay 54 on a black rubber strap straight from the catalogue, with the T-fit clasp. Rubber is not a compromise here. It is one of the two ways this watch is officially sold.
A short bit of history (because it explains the colours)
The Black Bay 54 arrived in 2023 as Tudor's most literal piece of nostalgia yet, modelled on the Oyster Prince Submariner ref. 7922 from 1954 — the brand's first dive watch. The details are unusually faithful: a small crown with no crown guards, a domed sapphire crystal standing in for the old acrylic, and an aluminium bezel insert with no minute graduations at all in the first fifteen minutes, exactly as the 7922 had it.
Inside is the Calibre MT5400, chronometer-certified, around 70 hours of reserve, no date. Water resistance is 200m, double what the 1954 original managed.
But the detail that decides your strap is the dial. The 54 has a black domed dial with rose-gold coloured hands and applied markers, and warm gilt printing throughout the text and minute track. The handset is a mix: a snowflake hour hand, a pencil minute hand, and a lollipop seconds hand with a round lume pip.
That gold is the only warm thing on an otherwise cold steel watch. Which means Tudor has already told you what to do.
The best strap colours for the Black Bay 54 79000N
Brown — the one that understands the dial. This is my pick for the 54 and it is not close. The gilt printing, the rose-gold markers and the gold-outlined indices are warm, and brown rubber is the only colour in the range that agrees with them instead of ignoring them. Put the 54 on brown and the gold in the dial suddenly reads as deliberate rather than as a detail you had not noticed. It also finishes the vintage story the watch is already telling — 1954 case, 1954 bezel, warm strap. On the steel bracelet all that gold has nothing to talk to. This is the swap that makes people ask what the watch is. Brown Tudor Black Bay Rubber Strap
Black — the factory configuration. Tudor sells the 54 on black rubber, so this is as close to "correct" as an aftermarket strap gets. It keeps the watch looking like a tool, drops the weight against the bracelet, and lets the gilt do its thing without any competition from the wrist. If you want one strap that you never have to think about and that works with absolutely everything, this is it. It is also the easiest one to hand to someone who is nervous about changing the look of a watch they just bought. Black Tudor Black Bay Rubber Strap
Navy Blue — the everyday one, and the answer for the blue dial. Navy is the strap that makes the 54 feel like a summer watch without shouting about it. Against the black dial it reads as almost-black indoors and clearly blue in daylight, which is a nice trick on a watch this small — it changes character during the day. And if yours is one of the newer blue-dial Black Bay 54 references rather than the black 79000N, start here: same 20mm, same "Black Bay 54" selection, and navy is the obvious tonal match. Navy Blue Tudor Black Bay Rubber Strap
Bordeaux — the one for evenings. Deep burgundy against a gilt dial is one of the oldest good ideas in watches, and the 54 is the Black Bay that can carry it. At 37mm this watch slides under a shirt cuff in a way no other Tudor diver manages, and bordeaux pushes it further in that direction — it stops looking like a dive watch you dressed up and starts looking like a dress watch that happens to have a bezel. Not an everyday strap for most people. A very good second one. Bordeaux Tudor Black Bay Rubber Strap
One honest note on the LuxLine® straps. They are excellent, and on watches like the BB58 or the GMT the coloured line looks fantastic. On the 54 I would skip them. The whole design language of this reference is pre-1960s, and a contrast racing line pulls it somewhere modern — you end up fighting the watch. All four picks above are deliberately plain, and on this one reference that is the point.
If you want to go further in the vintage direction, leather is the natural move and the 54 wears it better than any other Black Bay: Brown Leather Strap for Tudor
Or see the full range for this case here: All Tudor Black Bay Straps
Getting the order right
Colour first, then the important bit: select "Black Bay 54" on the product page. Not "Black Bay 58", even though both are 20mm. Not "Black Bay 36", which is a different width entirely.
If you own more than one Tudor, these cover the sizes people mix up most:
- Tudor Black Bay Fifty-Eight 79030N Strap Guide — 39mm, 20mm lugs, different selection
- Tudor Black Bay 41 Blue 79230B Strap Guide — 41mm, 22mm lugs
- Tudor Black Bay 36 Ref. 79640 Strap Guide — 36mm, 19mm lugs
FAQ
What lug width is the Tudor Black Bay 54? 20mm. Tudor states 20mm for the reference, and every hands-on measurement confirms it. The 19mm figure you may have seen on some strap sites is incorrect.
Is the Black Bay 54 the same strap size as the Black Bay 58? Both are 20mm, but the cases are different — the 54 is 37mm and thinner. On Helvetus, select "Black Bay 54" so the strap is cut for the right case.
Does the Black Bay 54 come on rubber from Tudor? Yes. Tudor offers it on a steel bracelet or on a black rubber strap with the T-fit clasp, so rubber is a factory configuration for this reference.
What is the best strap colour for the Black Bay 54? Brown, if you want the gilt dial to make sense. Black, if you want the safest possible answer. The gold-toned hands, markers and printing are the thing to match.
Will a Black Bay 54 strap fit the blue-dial version? Yes — the blue Black Bay 54 shares the same 37mm case and 20mm lugs. Same selection, just pick a colour that suits the blue dial.
Final thoughts
The 54 is the Black Bay that people buy and then never take off, and a strap is what turns it from a watch you own into a watch you wear. Lighter than the bracelet, better on smaller wrists, and — because of that unusually wide 20mm strap on a small case — a genuine change of character rather than a detail nobody notices.
Helvetus straps are cut for this exact case, so you get a clean, gap-free fit at the lugs. Every rubber strap carries a lifetime warranty, shipping is free worldwide with no import costs, and over 50,000 customers have already made the swap.
