New here. Just picked up an almost mint 3592.50 with the hesalite front and sapphire back, gold 863 movement.

I thought all speedmasters were 42mm but the total bezel on this one is 40mm 42mm to the end of the crown. Is this usual? I did buy it in Japan, I wonder if they had some smaller ones made?

serial number is 48272619 if that helps!

Nicely faded tritium dials but unfortunately just serviced and had the hands replaced so they do look a little white.

A couple of quick pics!

 

Yes, if you read up on the history of the Speedmaster you'll see that your measurements are correct. The 42mm measurement is the default case size, however since there are crown guards the bezel size is 39.7mm. The first Speedmaster, which came without crown guards, was this size, as is the "First Omega In Space" reissue that came out a few years ago.

 

Thanks for the replies. I can feel this is going to end up being a dangerous hobby as I am prone to getting to deep into things! (Other hobbies being cameras and guitars!)

Anyway, I'd really like to confirm this is the standard size as everything I have read seems to point that they should be 42mm across the bezel and 44mm to the end of the crown. Mine is definitely 40mm across the bezel and 42mm to the crown. See pic.

I'll go and compare with another one today. I'm so lucky living in Japan with access to so many beautiful watches.

Any idea how old this is from the serial number. I heard this particular run was hard to date as the serial numbers aren't in sequence.

 

Your watch should be 42 mm to the crown.. Speedmaster 9300 is 44mm to the crown....

 

I thought I remember reading somewhere that Omega's official measurements were from 8:00 to 2:00, which is often a slightly longer distance than 9:00 to 3:00. I could be wrong.

 

I think your right...

 

I don't know where you're getting your information from but it is incorrect. The Speedmaster Professional has always been 39.7mm bezel width, with 42mm being the size to the CROWN GUARDS, not the end of the crown. See here:
http://www.hodinkee.com/blog/a-vintage-watch-nerds-critical-dissection-of-the-new-omega-s
And Here:
http://forums.watchuseek.com/f20/speedmaster-pro-size-question-820516-post5998672.html#post5998672

Also, a large tape measure like the one you're employing is a poor choice for measurements under 10cm as the end piece can add or subtract a few MM here or there due to uneven tension and drift.
Your watch is correct in its sizing.

As for the serial numbers, it's very hard to date them due to the "parts bin" style of assembly that Omega uses. Also, what really is the real "date" of a watch; when it was assembled, when the movement was finally put together whole, when the parts were smelted or forged, when it was sold, when it was imported, etc. etc. It's much better to judge the merits of your watch based off it's tangible features (Tritium vs Superluminova, 861 vs 1861, 17 vs 18 jewels, 1171 vs 1450 vs 1479 vs 1499 bracelet etc.).

 

I really love the look of this watch. I hope to add it in one day. Japan seems to be a haven for Omegas!