The Breitling Watch Source Forums

Hey guys, I'm just curious to know how people monitor the accuracy of their watches? I know different watches have acceptable ranges of accuracy (ie + or - 6 seconds a day). However, how do you know your watch is actually falling within that acceptable range of accuracy? I set my watch to the SECOND according to the US national time at time.gov and wanted to see how accurate it was. I noticed that within the past 24 hours it's changed maybe 3-5 seconds off. I'm not really sure because even the Java app is a bit off as well. Either way, obviously some watches are more accurate than others, and some can be faulty upon delivery (hence the need for a warranty). So, how does one know their watch is falling within the acceptable range of accuracy?

Set as you describe. Wait 30 days while wearing/winding as usual (do not let it run to a stop -- duh) then check again and divide by 30. That will give you a better running average and not be subject to the vagarities of what you might be doing/positioning with/of wrist on a single day. COSC is -4/+6 sec/day. Outside of that and the watch should be regulated to get it there (most ADs can do this)

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Chronomat, Steel/Gold, MOP Dial, 2-tone band (2008)
Super Avenger Black Baton Dial (2009)
Bentley B04 GMT Silver Dial (2013)
Avenger Blacksteel Baton Dial (2014)

Hi !

The way I do it which may or may not be the correct manner is very much in the same way that you are doing it. I set my watches to a standard such as calling the time feature on my ATT phone and then I become a geek and/or anal and monitor it for the next few days or even a week or two. I do this only when I first get a new watch or when I get it back from having it service by Breitling USA; henceforth, I am not this nutty all of the time thank God with my watches. If the watch operates within the parameters' established by COSC which presently is synonymous with the current Breitling standard then it is accurate - that simple ! Also remember that your activity, climate, and yes even the earth's gravity will have a say on the accuracy of an automatic watch. As a result every week or two I reset the time when the difference is more than a minute - but I like to keep my watch a minute fast - just habit !

An inexpensive/cheap Casio F91 would be more accurate than an automatic watch - but are you simply buying the watch to tell time or is it a timepiece to be appreciated and mechanically admired by "watch people" and "layman" alike -hmmmmmmmm. Only you can answer that question for yourself. I hope that I was able to answer your question !

Best Regards,

Enezdez

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IWC - Big Pilot 5002 - 01
IWC - Pilot Chrono 3717 - 04
Panerai - 183
Omega - Speedmaster 145.012 / 67
Rolex - Explore II (Black Dial) - 216570
Rolex - Explore I 114270
Blancpain FF 5015

So in 30 days my watch can be off by as much as 180 seconds?

Also, I have to keep winding it? Yes, this is an honest question, I've never had a watch that doesn't require a battery , so I really don't know. I assumed the "48 hour power reserve" meant that it would keep ticking for 48 hours if I wasn't wearing it. I just assumed that I didn't have to wind it if I kept wearing it...is this wrong?

No your not wrong - if u keep wearing it you should not have to wind it !


Best Regards,

Enezdez

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IWC - Big Pilot 5002 - 01
IWC - Pilot Chrono 3717 - 04
Panerai - 183
Omega - Speedmaster 145.012 / 67
Rolex - Explore II (Black Dial) - 216570
Rolex - Explore I 114270
Blancpain FF 5015

Second question first: 42 hour reserve means just that. You can leave it on the dresser for the better part of a weekend without it stopping. After that, gotta wind it!
First question: Yes, technically. Most do not fall that far. If it is right at the limit, and you have a moderately understanding AD, you can get it regulated even so. But let us keep our heads here. 180 seconds is 3 minutes a month. If you run that close to perfect in your life I would suggest a superquartz movement!

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Chronomat, Steel/Gold, MOP Dial, 2-tone band (2008)
Super Avenger Black Baton Dial (2009)
Bentley B04 GMT Silver Dial (2013)
Avenger Blacksteel Baton Dial (2014)

I was concerned about my Steelfish at first. It would gain about 6 - 10 sec a day for the first two months. Now it gains about 1 - 2 sec per day. It also depends on how you store it when not wearing it. Upside down, backwards, etc. If you search this site you will see all of this in detail. I will say that my Seawolf (I have had it for about two months) is still gaining 6 - 10 sec per day and it has the same B 17 movement. I will continue to be patient with it. I have a Fortis that was gaining 15 sec per day. I had it regulated. Now it loses 8 sec per day. It is much easier to adjust for 15 sec fast (or any amount fast) than to adjust the slow. With all of that said, if seconds matter, get the Airwolf.

R/

Well, I can say that my Superquartz Airwolf is DEAD on. I use the US national time observatory via telephone. About 5 weeks after the original set, I just checked it today, and it's still accurate to the millisecond. One thing that surprises me just a tiny bit is that my Co-Pilot is also dead on. Rather nice that the Co-Pilot isn't going to start running off at another time pace than the watch.

Now my Chronomat on the other hand, I still don't know for sure. As it's a special occasion watch, I don't wear it every day and haven't had it running for long enough to really notice the accuracy. I think once I wore it two days in a row, and it looked like it gained 4-5 seconds in a day. I need to get it through the break-in period, too.

Still haven't decided for sure on a winder, but I think I'm going to probably get one. I just still haven't found one that is perfect.

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Chris
Club Member #0070
2009 TT Chrono Evo w/Rose gold, blue face
2009 Airwolf w/black face, Co-Pilot module
2009 TT Lady Cockpit w/Mother-of-Pearl, Diamond face for the wife

You can check it against your cell phone time. It can vary depending on how much you wear it. E.g. can run fast during the day while you're wearing it and then slow down a bit at night while it unwinds. As someone else mentioned, if you want accuracy, a digital Casio will be more accurate. But automatic watches are the most complex mechanical devices on the planet so therefore much more interesting! I'm sure it's a great watch and keeps good time, so don't worry and enjoy.

Your best bet to have an accurate comparison is to sync your computer's system clock to a good ntp time server. Macs do this automatically using one of apple's servers. I'm not sure about windows, but I'm sure there are apps to sync your clock. Assuming you do that, the time on your machine will remain steady to within a few milliseconds a day. time.nist.gov is a good server too. Ideally you want a server that you are geographically close to, but ntp is fairly clever about correcting for latency.

That said, there are a lot of variables that affect accuracy. How you store it(crown up, crown down, etc). Temperatures, etc.

On windows machines simply double click your clock icon in the lower right corner. Select internet time. Choose to automatically synchronize. Choose a server and hit update now. It will automatically update once a week to stay in sync.

If youi live in the U.S., here's the website I find helpful from the U.S. Naval Observatory.
http://tycho.usno.navy.mil/simpletime.html