Ultimate guide to Omega Speedmaster sizes

Ultimate Guide to Omega Speedmaster Sizes

I’ve seen many people ask about Omega Speedmaster sizes. Usually in terms of the “will it fit” conundrum.

They’ll say something like: “42mm, that’s too big. I’ll go for the FOiS (First Omega in Space, a reinterpretation of the CK 2998 design). It’s smaller.”

Technically, that’s not true.

Let’s have a close look at the dimensions of various Speedmaster models.

This article was originally published on February 23, 2018. It was updated and newly published on July 24, 2022.

What if I told you, that 42 mm isn’t necessarily 42 mm in terms of fit?

You’d probably question that. “But the manufacturer said…”

Forget what the manufacturer said. The diameter doesn’t always determine how it’ll fit.

The fit is determined by how the watch spans from one side of the wrist to the other, where the lug-to-lug size is what matters.

For example, a 43 mm watch with hidden lugs, or a “lugless” design with the lugs being recesses in the main bloc of the case will obviously wear smaller than a 39-40 mm with a lug-to-lug distance of 48-50 mm.

Or smaller than a Longines Legend Diver, where the lug-to-lug distance is – with the diameter of 42 mm not even suggesting that – a whopping 56 mm. That’s the same as in the 46 mm IWC Big Pilot’s Watch, and a hair short of the 47 mm Panerai reissues.

So, what is it like with the Omega Speedmasters?

In case of the Speedmasters, the diameter is not the thing to be concerned about, because Omega provides the diameter including the crown and pusher guards. That doesn’t have any influence on the lug-to-lug distance.

The bezel diameter is still 39.7 mm, just as it was in all Speedmasters since the 2915-3.

The first Speedmasters (CK 2915), ref. 2915-1 and 2915-2 had a diameter of 38 mm. With the 2915-3, this was increased due to the use of a new bezel type, one with an insert as we know it today, instead of the single-piece engraved bezel.

Lug-to-lug, the Pro measures 48 mm. Some people will say “it’s too big, I’ll get the smaller FOiS.”

The fun part is, that the FOiS won’t cause the watch to have the tips of the lugs further from the edge of the wrist.

That’s because the straight lug cases, both vintage, and modern ones, have the same lug-to-lug distance of 48 mm.

Ultimate guide to Omega Speedmaster sizes
Omega Speedmaster Pro on a 19 cm (7.5 inches) wrist.

Weight distribution

Oddly enough, the apparently smaller FOiS might seem heavier – due to the lack of crown guards and a sapphire crystal (obviously, heavier than hesalite).

The center of gravity sits slightly higher in the FOiS.

“So, which is bigger?”

In terms of the area occupied, the Pro. The wide lugs and the crown guard certainly make it look bulkier than it really is.

In terms of concerns about lug overhang, neither. They’re the same.

“What about the contemporary cal.9300 Speedmasters?”

Oh, that’s funny, because in this case, the diameters matter even less.

44.25 mm will likely appall some, but the lug-to-lug is…50 mm. Still less than a 42 mm Longines Legend Diver with its 56 mm though.

“Does it mean it’ll be comfortable, then?”

Not necessarily. They have a high-dome crystal in the case back, making them top-heavy on smaller wrists.

Not to mention that the bulk of the case flies high above the wrist itself.

“But what if I get the Co-Axial cal. 9300 reinterpretation of the 2915?”

That won’t serve you any better than the 44.25 mm ones.

No, it might not have the crown guards, but the lug-to-lug is still about 50 mm, and it still has that bulky crystal in the back.

And again, the weight distribution kicks in.

“But there has to be something that’s not top-heavy!”

There is. The Speedmaster “Racing”, first introduced at Baselworld 2017. Omega trimmed the high-dome case back crystal.

Still, if the lug-to-lug you’re more comfortable with would be 48 mm, go for the Pro.

“But I don’t like manually wound movements, I prefer automatic”

That’s fine. Get a Speedmaster Reduced, if you’re OK with a modular automatic.

Ultimate guide Omega Speedmaster sizes
Omega Speedmaster Reduced.

“But it’s too small!”

The diameter of the Speedmaster Reduced without the crown and pushers is 38 mm and the lug to lug is 45 mm. If you think that’s too small, you’ll have to settle for a Speedy with a manual movement.

“I still don’t know if it’ll fit and which one I prefer”

Then go and try some of them on.

Seriously. It’s best to take a walk, think, try them on, and not rely on the individual experiences of others.

It feels different for everyone because every wrist is different. Just like with shoes. Two people might have the same shoe size, but that doesn’t mean that the same shoe will fit them identically.

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6 thoughts on “Ultimate Guide to Omega Speedmaster Sizes”

  1. Sipping a Laphroaig Quarter Cask as I type this.

    I’m confused, is there any real difference between a 3513.52 movement and a 3513.50 movement? Looking at a couple of Speedmaster Dates. Also, looking at a Speedmaster Reduced but there is quite a jump in price and I just don’t know the ins and outs of watches. Is the Speedmaster Reduced (1999, 3220 movement) so much better or more likely to hold it’s value so as to justify the extra $700 – $800 dollar additional cost over the Speedmaster Date?

    If your ever in Florida (Vero Beach) look me up. I did some Ocean Racing and a lot of bluewater cruising as a younger man. And I have an interesting collection of Whiskies from Islay.

  2. Wondering if you can tell me the lug-to-lug dimension for the 3210.51.00 Speedmaster Black Red Dial? Thanks!

  3. Hi Michał,

    Thanks for a great walkthrough of the different sizes, and perceived sizes.
    I have a question. Are there any models of the Speedmaster (Pro, Reduced, or other model) that does not have the crown guards, other than the FIOS? But still has the all-black dial..

    I prefer without crown guards as the case looks less chubby, more classic and elegant, but the FIOS I do not like as much because of the shape and color of the hands. I wish they had made the FIOS with the white straight hands, then it would have been perfect (to my taste 🙂

    And as a side note, I actually prefer the Reduced design as I prefer the flatter subdials over the almost pie-pan looking ones on the pro. I just love that the only difference from dial to subdial is that tiny difference in height…(a small detail that I have never seen anyone mention…)

  4. Great information, thanks. I was thinking of purchasing a cheap 3513.50 but now I will probably hold out for a 3570.50. Thanks again for the infromation.

  5. Still somewhat confused. A model 3513.50 has a stated diameter of 39mm while the 3570.50 is 44.25mm, yet they both have the same bezel diameter and are both 48mm in length? I am a big guy (over 8″ diameter wrist). Will a 3513.50 look tiny on me compared to a 3570.50? I currently have a 2538.20 (41mm) and it looks a little small on me. I am in a place where I can’t physically compare.

    1. Michał Kolwas

      The 3570.50 is not 44.25mm in diameter. It’s a standard Speedy Pro, 42mm in diameter (including the extended right flank acting as a crown and pusher guard), 39mm bezel, 48mm lug to lug.

      The 3513.50 automatic (Valjoux base) is 39mm including the crown and pusher guard, which by extension makes the bezel way smaller (circa 37-38mm).

      The lug-to-lug of the 3513.50 is 45mm, which is less than that of the “Great White” (47mm lug to lug) that you have, and less than the 3570.50 Pro (48mm lug to lug). So, the 3513.50 will wear smaller than either the 3570.50 or the 2538.20.

      The 2538.20 has a very different silhouette, given that the lugs and flanks of it are far sleeker than that of the asymmetric Speedy case. The bottom line is that the 3570.50 will simply appear more chunky, and cover a larger surface area, so to speak.

      All in all… Will the 3570.50 wear the largest of the three (3513.50, 2538.20, 3570.50)? Yes. Will it wear bigger than the 3513.50? Considerably.

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