Accuracy - GMT Master II

[Greg9999]

My new GMT Master II (not the ceramic bezel, but the 16710) is about 2-3 seconds slow per day. Is this normal?

[EvEr34]

Originally Posted by Greg9999

My new GMT Master II (not the ceramic bezel, but the 16710) is about 2-3 seconds slow per day. Is this normal?

Nothing wrong with that. Enjoy the watch

[Robb]

Yes its normal!

[Tools]

I'm not partial to a slow watch...I prefer to have it a second or so fast each day..

Still, -2 is within COSC standards..(-4/+6)

You don't say how long you've had it running continuously but it's my experience that it takes about a month for a Rolex to "settle in" and give consistent readings.

As I recall my GMT was a second or two slow each day but has settled down to about 1/2 second per day and is my most accurate. Second best is a Sub that is +1 1/2 per day and the worst performer is an EXP II at about + 3 to 4 Sec per day.

They can be regulated very well if your watchmaker knows how it is working while on your wrist.. Set it to a known accurate time source....now...walk away. Check it again in a week (7 days) and check the time then; now divide by 7 to get an average.

Armed with this knowledge over a week or better yet, averaged over a couple of weeks, your watchmaker should be able to regulate it for you..

The 16710 seems to be able to be postion regulated somewhat. Try laying your GMT face down at night when you retire as a routine... This should speed it up slightly at night while you sleep

[BiG JeEzY]

Originally Posted by Tools

I'm not partial to a slow watch...I prefer to have it a second or so fast each day..

Still, -2 is within COSC standards..(-4/+6)

You don't say how long you've had it running continuously but it's my experience that it takes about a month for a Rolex to "settle in" and give consistent readings.

As I recall my GMT was a second or two slow each day but has settled down to about 1/2 second per day and is my most accurate. Second best is a Sub that is +1 1/2 per day and the worst performer is an EXP II at about + 3 to 4 Sec per day.

They can be regulated very well if your watchmaker knows how it is working while on your wrist.. Set it to a known accurate time source....now...walk away. Check it again in a week (7 days) and check the time then; now divide by 7 to get an average.

Armed with this knowledge over a week or better yet, averaged over a couple of weeks, your watchmaker should be able to regulate it for you..

The 16710 seems to be able to be postion regulated somewhat. Try laying your GMT face down at night when you retire as a routine... This should speed it up slightly at night while you sleep

Yes Larry gives an excellent answer. Being -2 to -3 seconds each day is excellent for a mechanical watch. However, I also would rather have it run a little bit faster each day rather than slower.

That way, if my watch gets too far ahead eventually, I can just pull out the crown, stop the movement, and wait for the time to catch up to my watch again.

Its a neat trick to do, that way you dont have to adjust any of the hands at all.

If you wish to have your watch regulated, it is not hard to do at all. Its usually just in and out.

[Greg9999]

Originally Posted by Tools

I'm not partial to a slow watch...I prefer to have it a second or so fast each day..

Still, -2 is within COSC standards..(-4/+6)

You don't say how long you've had it running continuously but it's my experience that it takes about a month for a Rolex to "settle in" and give consistent readings.

As I recall my GMT was a second or two slow each day but has settled down to about 1/2 second per day and is my most accurate. Second best is a Sub that is +1 1/2 per day and the worst performer is an EXP II at about + 3 to 4 Sec per day.

They can be regulated very well if your watchmaker knows how it is working while on your wrist.. Set it to a known accurate time source....now...walk away. Check it again in a week (7 days) and check the time then; now divide by 7 to get an average.

Armed with this knowledge over a week or better yet, averaged over a couple of weeks, your watchmaker should be able to regulate it for you..

The 16710 seems to be able to be postion regulated somewhat. Try laying your GMT face down at night when you retire as a routine... This should speed it up slightly at night while you sleep

- The watch was purchased new 1 month ago
- My accuracy calculation is based the WWV time standard signal (over the air, not through a PC). I have let it run 10days, in that time it has lost 23sec. So that's 2.3sec per day.
- I never take it off my wrist (sleep, shower,)

[BiG JeEzY]

Originally Posted by Greg9999

- My accuracy calculation is based the WWV time standard signal (over the air, not through a PC). I have let it run 10days, in that time it has lost 23sec. So that's 2.3sec per day.
- I never take it off my wrist (sleep, shower,)

Thats very good results! Glad to hear thats the watch is always on your wrist. Thats where it was made to be at all times.

[Tools]

If you don't plan to have it regulated any better - and believe me, sometimes you can screw it up rather than making it better - here's what you do.

Given it's a mechanical watch and it will gain/lose and need to be reset ocassionally.

If you know it is consistent -2 seconds each day, start out the month with it set 30 seconds fast. By mid-month it will be spot on, and by the end of the month it will be 30 seconds slow, ready to re-set and start again.

This way, at any time in the month you know almost to the second what time it is. For example, on the seventh of the month your watch will be showing 15 seconds ahead, by the 23rd of the month you will be showing 15 seconds behind.

[JJ Irani]

Originally Posted by Greg9999

My new GMT Master II (not the ceramic bezel, but the 16710) is about 2-3 seconds slow per day. Is this normal?

Nothing to worry about, Greg.

My Blue Sub was running like 2 seconds slow per day when it was new.

Today it is spot-on. Give any new watch around 6~8 weeks to "break-in".....and after that it runs very accurately.

JJ

[BiG JeEzY]

Nice avatar Larry!

[Tools]

Originally Posted by BiG JeEzY

Nice avatar Larry!

Thanks...

[SPACE-DWELLER]

Originally Posted by Greg9999

My new GMT Master II (not the ceramic bezel, but the 16710) is about 2-3 seconds slow per day. Is this normal?

Quite normal, as the others stated since the COSC specs are minus 4 to plus 6 secs/day.

If your GMT IIC is losing time with those 2 - 3 secs/day, in fact it IS running "precisely" and furthermore with a 99.99 pct. precision! You must realize that this is an automatic mvt. and that you cannot expect 100 pct. accuracy.

For how long have you owned the GMT IIC? Since you must know that the mvt. needs "breaking in" and after a month's time you can have a better idea of its precision.

By that time you can have it regulated by a Rolex-trained watch maker. It is an easy operation and should take ½ an hour at max.

[Dan Pierce]

Once again Larry is spot on. My GMT runs a little less that -2 sec per day and I set it as he describes. Works great.
dP

If you don't plan to have it regulated any better - and believe me, sometimes you can screw it up rather than making it better - here's what you do.

Given it's a mechanical watch and it will gain/lose and need to be reset ocassionally.

If you know it is consistent -2 seconds each day, start out the month with it set 30 seconds fast. By mid-month it will be spot on, and by the end of the month it will be 30 seconds slow, ready to re-set and start again.

This way, at any time in the month you know almost to the second what time it is. For example, on the seventh of the month your watch will be showing 15 seconds ahead, by the 23rd of the month you will be showing 15 seconds behind.

[blackeagle]

Accuracy after a month of breaking in is improving. For last 20 days as timed against time.gov my watch lost 18 seconds exactly. My old GMT that I wore for 22 years changed every time I had it serviced. The last 6 years it lost a minute a month.

I work out in a local gym with a retired Pan Am pilot/navigator who still has his original GMT. I asked him if he really relied on his Rolex for navigation purposes, and responded he sure did and did so for a number of years.

[bayhillrolex]

-12 seconds after 3 days (72 hours) or -4 seconds @ day

[Alcan]

Hi Greg, although your watch is already running within COSC specs, this might be of some help: