It might not be the first thing that comes to mind when buying a pre-owned or vintage Speedmaster, but what kind of accuracy should you expect from a pre-loved timepiece? Most of the buyers and collectors are more concerned about the watch’s aesthetics than the technical condition of the watch, it seems. Let’s have a closer look at the accuracy of the Speedmaster and what falls within acceptable parameters.

In my opinion, patina has become a bit of a buzzword. Sometimes, it is as if it is the only thing that matters when it comes to buying a pre-owned or vintage Speedmaster. Sure, it is important how a watch looks, but there’s more to it than the yellow or green color of hour markers. I’ve made the mistake once myself, by having only paid attention to the exterior of a Speedmaster. Does it have the right bezel, dials, hands, case back, etcetera? Those were the questions I asked myself.

Only when I received the watch did I find out that the caliber 861 movement was running terribly slow and had a number of replacement parts from other calibers. I got it fixed in the end, but it was an expensive lesson. I could’ve slapped myself on the forehead: one of the most important lessons that my Speedmaster mentor Gerard taught me, is to take note of the technical condition of a watch.

This article is about just that. Hopefully, it will remind you to think twice and ensure you obtain a stunner that is also a good runner. How can you identify a poorly or unserviced Speedmaster? What are the signs that a Speedmaster needs a proper service? Let’s find out.

Speedmaster Professional 145.022-76 - Speedmaster Accuracy

Accuracy on pre-owned and vintage Speedmaster watches

With the new Speedmaster Professional Moonwatch Master Chronometer, accuracy is not really an issue. With the certification by METAS, the watch has an average daily deviation of +5/0 seconds. My Speedmaster Pro with caliber 3861 is indeed dead on. If I put my Speedmaster Calibre 321 on a timing device, the average daily rate is around +8 seconds a day. According to Omega, this still an acceptable figure (the brand works to -1/+11 seconds per day on average for non-chronometer chronographs). And to me, that’s an acceptable number as well. But what if you buy a pre-owned or vintage Omega Speedmaster?

Speedmaster Accuracy

Caliber 861

Identifying a Speedmaster in need of a service

The problem — although some people might not see this as a problem — is that when you have a few Omega Speedmaster watches, you will probably rotate them a bit. This means that it might take a while to find out your watch is not running as it should. Only when it is terribly off, caused by a severe shock or drop, will you quickly find out that it needs a service. Now, according to a watchmaker that I consulted, there are a few things that could indicate that a Speedmaster is in need of a service. Or better said: an indicator it has not been serviced recently.

Rob Nudds (a former watchmaker himself) at the watchmaker’s bench in the boutique.

My watchmaker (not Rob) also gave me a disclaimer, that a lot of the following takeaways are often being discussed among watchmakers. A lot of watchmakers have their own way of working or way of doing things, so one thing I’ve learned during my discussions with him, is that a) it is not rocket science and b) there’s not just one way to find out. Or perhaps there is, and that’s the easy one: take your Speedmaster to a watchmaker, have him open and analyze it.

But that’s not always possible. Basically, you want to find out before you buy it. Now, you have to understand that a lot of vintage Speedmaster watches didn’t get proper servicing. Simply, because the watch didn’t indicate it needed one. A lot of people just have their watch serviced when it starts to run (very) slow, or just stops running entirely.

Speedmaster Accuracy

Calibers 3861, 1861 and 321

Easy give-away

It also shows how robust the hand-wound Speedmaster movement actually is. The Lémania based calibers 321, 861, and 1861 and other variations are truly amazing movements. They just keep running, even without losing too much time. One of the indicators of a Speedmaster in need of a service can be the amplitude of the balance. You will need a timing device for this, such as the Witschi Watch Expert 4. Often, the low amplitude of the balance of — let’s say — 220/230 degrees is an identifier for a movement that needs cleaning.

For illustration purpose only, there’s no Speedmaster movement on the Witschi

But, if it shows a proper amplitude of around 300 degrees, it doesn’t necessarily mean the watch is running fine. Confusing, eh? It can still mean that the movement is dry (no oil), or has worn gears or gaskets that definitely need to be replaced. As I wrote above, the only way to properly find out is to have the Speedmaster opened and the movement examined by a watchmaker.

Slow runner

Now, you have to understand that Omega’s standards today are very different from its past standards. While the brand now uses Master Chronometer, Chronometer, or the -1/+11 seconds per day on average for its non-chronometer mechanical watches, the acceptable deviations were bigger in the past. However, when a pre-owned or vintage Speedmaster runs terribly slow, like -30 seconds per day or worse, it is a solid signal that the watch needs to be serviced. In case of really abnormal deviation, it is often a sign of the watch having been dropped or having sustained a heavy knock. In that case, it needs to be serviced as well.

Honest Speedmaster Pro 145.022-76

Can it be adjusted?

The good news about a vintage Speedmaster with a movement running too slow or too fast is that it can be regulated. If you’re lucky, it is a matter of having it regulated properly by a watchmaker. Oftentimes, it is the case that a shock to the movement has simply moved the regulating arm, which controls the “active” length of the hairspring. This can be adjusted in seconds by an astute watchmaker. You can see this component in the image above, extending from the prominent jewel atop the balance arbor at around 200 degrees (it is a little silver-colored stalk with two brass dots on it).

From those two brass dots, regulating pins extend downward. The hairspring travels between these two pins and should be properly centered to ensure the spring is breathing evenly in all positions. If the hairspring is off-center here, it can lean against one of the pins in certain edge positions, for example, when your arm is dangling by your side, and perform as if the hairspring were much shorter than it is. If the “active” length of the hairspring is shorter than it needs to be, the watch will run fast. This kind of concern does not necessarily require a full service.

However, if the problem cannot be fixed by this adjustment or by simply demagnetizing the watch, the watch may need a full service. At this point, it would be wise to expect some parts may need replacing. But in any case, vintage or pre-owned Omega Speedmasters can have a proper and very acceptable performance when it comes to accuracy.

Speedmaster Professional 145.022-76

Calculate service costs

My own rule of thumb when buying a pre-owned or vintage Speedmaster is: if there’s no proof of service history, it has not been serviced. To me, it is as simple as that. Servicing a pre-owned watch (and especially a vintage Omega Speedmaster) is not cheap. You should always keep a warranty or invoice whenever you have work done on it. If a seller can’t show you an invoice of a service done in the last 3–5 years, just consider it unserviced and in the need of a service.


In some instances, the case back can give you some clues. Is it clean? Does it look like it has sustained unnatural damage? Is it possible it has been opened with the wrong tools? Look for deep scratches or unsightly burring on the case back notches. Regardless, it is always worth seeing the movement. Is it clean or filthy? Do the teeth of the visible gears look sharp? Are they burred? Are they worn? Can you see any sign of swarf (little bits of metal torn from components due to shock or excessive wear)? And talk to the seller. Ask how the watch winds. How long does it run for when fully wound? Is the watch quiet or does it make a tinny sound when ticking? The more information you can glean before purchase, the better.

Omega is very transparent in its pricing for servicing watches. It is all on the brand’s website here. Just make sure that you indicate what you want to have done. And, perhaps more importantly, what you don’t want to have done to your watch. There are a lot of independent watchmakers out there who are also perfectly capable of servicing a (vintage) Speedmaster. Just make sure to ask them upfront if they can source all the necessary parts.

More questions about Speedmaster watches? Go here.