Here's a number that should decide your strap.
A standard Tudor 1926 is 9.2mm thick. The 1926 Luna — the same 39mm case, with a moon phase added — is 10.1mm. Tudor spent exactly nine tenths of a millimetre to fit the complication in, and on a watch whose entire appeal is how thin it is, that's a real price to pay. Reviewers of the standard 1926 tend to lead with the thinness before they mention anything else.
Now consider what a strap costs. A padded, structured dress strap can add three or four millimetres underneath the caseback — three or four times what the moon phase cost. You can undo Tudor's engineering with one bad purchase, and most people do it without noticing.
So the rule on the Luna is simple and it comes before colour: flat, thin, and sitting directly against the caseback.
Fit and size
The Tudor 1926 Luna, refs M91560-0001, -0002 and -0003, is:
- 39mm steel case with a polished finish
- 21mm lug width
- 10.1mm thick, 100m water resistance
- Smooth polished steel bezel, sapphire crystal
- Satin sun-brushed dial with applied numerals and a moon phase indicator
- Calibre T607-9, 38-hour power reserve
You want 21mm with a curved end — the case is round with a defined shoulder at the lugs.
Order from here and select 21mm: Curved FKM Rubber Straps – 18mm to 22mm.
21mm is a width most makers skip entirely, jumping from 20 to 22. Ours is cut in it as standard and the size is named in the collection itself, so you can confirm it before checkout rather than after.
One name, four sizes, three different widths
This is the trap, and it's the reason so many 1926 owners end up with the wrong strap.
| Tudor 1926 | Case | Lug width |
|---|---|---|
| 1926 36mm | 36mm | 19mm |
| 1926 Luna and 1926 39mm | 39mm | 21mm |
| 1926 41mm | 41mm | 22mm |
Same collection, same name, same dial language — and three different numbers. Nothing on the watch tells you which you have, and "Tudor 1926" as a search term returns all of them mixed together.
Worth knowing before you shop elsewhere: at least one published review of a 39mm 1926 lists it as 20mm. It isn't — Tudor's own specification says 21mm, and so do the retail product records. On a width this uncommon, a millimetre in either direction means a strap that either won't seat or won't sit still.
Thin is the whole point, so protect it
Back to the arithmetic from the top, because it drives every material decision on this watch.
At 10.1mm with a polished case and a smooth bezel, the Luna is built to disappear under a cuff. That's what a 1926 is for. Three consequences follow:
- No padding. A bolstered or heavily lined dress strap adds height where the watch has none to give. If you go leather, go unlined.
- No bulk at the lug ends. The 1926's lugs are slim and cleanly finished; anything that bunches where the strap meets the case makes a delicate watch look thick.
- Rubber is thinner than you think. FKM sits flat against the caseback and doesn't compress or curl at the ends the way a soft leather strap does after a summer. On a 100m watch with a screw-down crown, it's also the only material you never have to think about.
None of that stops you dressing the watch properly — it just rules out the one category of strap most people buy for a watch like this.
A night-time complication on a daytime watch
Now the colour decision, and it's more interesting than usual because of what the Luna actually shows you.
A moon phase is, by definition, about the night. Tudor put that on three dials: black, blue and champagne, all satin sun-brushed with applied numerals. Which gives you a genuine choice about whether the watch tells one story or two:
- Black or blue dial — complete the idea. A dark strap continues the night-sky logic straight through to the buckle, and the moon disc becomes the one bright element on the entire watch. This is the version that looks designed rather than assembled.
- Champagne dial — the contradiction is deliberate. A moon in a warm gold sky is a lovely conceit, and it wants a warm strap to finish it. Trying to force a champagne Luna into the night-sky reading with a black strap leaves the dial stranded between two ideas.
So look at your dial first. It decides the temperature; the picks below decide the rest.
The 4 best straps for the Tudor 1926 Luna
1. Blue — the night sky, and the most on-brief strap the watch has
Start here, particularly on the blue dial where it's simply the obvious move.
Blue is what a moon phase is set against, and running it from the dial through to the buckle turns the complication from a detail into the theme of the watch. The moon disc then reads as the only light in the picture — which is exactly the effect the complication is trying to produce and which a steel bracelet flattens completely.
On a black dial it works too, as a slightly softer version of the same idea. Go deep rather than pale: a bright blue reads sporty, and this watch is not that.
Shop: Blue Curved FKM Rubber Strap – 21mm
2. Black — the formal default, and the thinnest-looking option
The safe answer, and on this watch it does something specific beyond being safe.
Black recedes more completely than any other colour, so a 10.1mm case on a black strap reads thinner than the same watch on anything lighter. On a watch built around slimness, that's not a small thing. It also completes the night reading on the black and blue dials, and it's the version you can wear anywhere without thinking.
If you're buying one strap for the Luna and you want it to be the one you never reconsider, buy this.
Shop: Black Curved FKM Rubber Strap – 21mm
3. Brown — for the champagne dial, and the one Tudor themselves leans on
The 1926 has been sold on brown leather from the factory across the range, and on the champagne Luna it's the pairing that makes the warm-sky version of the watch make sense.
Brown meets the champagne dial and the gold-toned elements without competing with them, and it takes the Luna somewhere unmistakably classical — a moon phase in a warm case on a warm strap is about as traditional as watchmaking gets. It's also the most forgiving option if you wear the watch with a suit more often than not.
Medium to dark rather than tan. A pale brown against a champagne dial removes the contrast the case needs to define itself.
Shop: Brown Curved FKM Rubber Strap – 21mm
4. White — the one that answers the moon itself
The clever pick, and it's specific to this reference in a way none of the others are.
The whole visual of a moon phase is a pale disc against darkness. On a black or blue Luna, a white strap picks up that disc — the one bright element the complication adds — and repeats it at the wrist. Nothing else on the watch is white, so the reference is unmistakable once you see it.
It's a summer strap and a bold one on a dress watch, so treat it as a second or third rather than a first. But of everything on this list it's the pick that shows you actually looked at what the watch does.
Shop: White Curved FKM Rubber Strap – 21mm
Two more: bordeaux is the dress colour that isn't black and suits the champagne dial nearly as well as brown, and beige is the lightest way to warm up a champagne Luna without going brown.
The full 21mm range is here: Curved FKM Rubber Straps.
Quick answers
What is the lug width of the Tudor 1926 Luna? 21mm, on the 39mm case.
Is that the same as other 1926 sizes? No. The 36mm 1926 is 19mm and the 41mm is 22mm. Three sizes, three widths, one model name.
How thick is the Luna? 10.1mm, against 9.2mm for the standard 1926 — the moon phase costs 0.9mm.
What kind of strap should I avoid? Anything padded or heavily structured. On a case this thin, a bolstered strap adds several times what the complication did.
Curved end or straight end? Curved. The case is round with a defined shoulder at the lugs.
Which colour suits it best? Check your dial. Black and blue want a dark strap that completes the night-sky idea. Champagne wants a warm one — brown or bordeaux.
Getting one
The Luna is the only Tudor with a complication beyond a date, and the only one in the catalogue that isn't dressed as a tool. That makes it the one Tudor where the strap should be chosen the way you'd choose one for a proper dress watch — thin, considered, and matched to the dial rather than to a job.
Every Helvetus rubber strap carries a lifetime warranty, ships free worldwide with no import costs, and comes in 21mm as standard rather than as a special order. More than 50,000 customers in over 60 countries have bought from us.
Check your dial, keep it thin, and start with blue or black — the moon looks better against a dark sky.
