Accuracy question from a first time Rolex owner (GMT II C brand new)

[padi56]

Originally Posted by James M

That's great, wish mine was that accurate.

As it is its just falling within COSC so as long as it stays that way I'm happy.

You guys make me smile with this accuracy stuff even at the bottom of the scale a modern day Rolex is 99.994% accurate.And seeing that there are 86400 seconds in 24 hours for any mechanical watch to perform consistent to this standard is quite a mechanical marvel.My own 5513 from the latter part of the 70s last set it then,just checked its gained 0.559999999 of a second in 33 years but again a could live on fantasy island.

[James M]

Originally Posted by padi56

You guys make me smile with this accuracy stuff even at the bottom of the scale a modern day Rolex is 99.994% accurate.And seeing that there are 86400 seconds in 24 hours for any mechanical watch to perform consistent to this standard is quite a mechanical marvel.My own 5513 from the latter part of the 70s last set it then,just checked its gained 0.559999999 of a second in 33 years but again a could live on fantasy island.

Agreed I think it's pretty amazing that a mechanical watch can be -+30 a day so a few seconds is no big deal.

Not being spot doesn't detract from my enjoyment of the watch as long as its consistent but being as close to spot on is a bonus.

A wide variation such as the OP is getting would worry me as it would seem to indicate a problem.

[padi56]

Originally Posted by James M

A wide variation such as the OP is getting would worry me as it would seem to indicate a problem.

Would agree but depends on how and what parameters he was testing his watch too as he states about this or about that, when you test you want as near as possible precise testing .Could be something simple like a slightly tangled hairspring a little bit of oil on hairspring. Even its been known for mechanical watches not to run on certain people but its a strange one.And in over 30 years of being around Rolex watches have never heard of one thats performs like what the OP describes.And afraid no purely mechanical watch from any brand and price will give 100% accurate time there will be almost daily tiny divinations.This is why the COSC test is too a AVERAGE of between -4 to + 6 seconds over any 24 hour period.And when testing the movement on the first 10 days of testing the movement could vary either way by up to 10 seconds over a 24 hour period and still pass the COSC test.

[James M]

It wasn't till I read on this site that it should be averaged over several days. Prior to that I would check after 24 hours against wwp.greenwichmeantime.com then reset and test it again for another 24 hours.

You live and learn!

[Psmith]

Originally Posted by James M

That's great, wish mine was that accurate.

As it is its just falling within COSC so as long as it stays that way I'm happy.

Me too...

Usually I find that mech watches run a bit fast, but as long as it is within COSC and consistent then I'm happy

The Exp II was a bit of an exception

[Elementa]

Outside of a problem scenario (which the op might have), I long ago stopped timing my watches. It's really distracting and unless folks start showing up to meetings with stopwatches, a minute here and there won't matter.

[jagwap]

You said you were using your home and work computers to time it.

Any chance your work and home computers are 15-20 seconds different? It would be just poor luck if this turned out to be the problem. But your watch may be fine.

[Kallagtunet]

Originally Posted by jagwap

You said you were using your home and work computers to time it.

Any chance your work and home computers are 15-20 seconds different? It would be just poor luck if this turned out to be the problem. But your watch may be fine.

As said in earlier post now using gov.time site both at work and at home. Same probem with speed variance based on activity level...

[padi56]

Originally Posted by Kallagtunet

As said in earlier post now using gov.time site both at work and at home. Same probem with speed variance based on activity level...

First you cannot test any watch the way you are testing it say over a few hours of activity.To do a accurate test first wind the watch fully 40 crown turns clockwise.Then sync watch if you have a quartz watch that will do for this test,after sync just wear as normal.Check time once daily with same setting source over 5 full days, then average out the lose or gain over those five days,but take your watch off at night.If results are still way off the COSC spec a AVERAGE of -4 to +6 seconds over any 24 hour period your watch needs checking by RSC.

[Kallagtunet]

Originally Posted by padi56

First you cannot test any watch the way you are testing it say over a few hours of activity.To do a accurate test first wind the watch fully 40 crown turns clockwise.Then sync watch if you have a quartz watch that will do for this test,after sync just wear as normal.Check time once daily with same setting source over 5 full days, then average out the lose or gain over those five days,but take your watch off at night.If results are still way off the COSC spec a AVERAGE of -4 to +6 seconds over any 24 hour period your watch needs checking by RSC.

I understand what you say and that it is the average over 24 hous over several days that is the baseline for adjustment but what i really do not understand is how the RSC are going to adjust based when the variance due to activity levelmis so is so big. On a days where i have high activity level a running session and much walking it will gain 20 - 25 seconds but on a day on a regular office day witout any exerzise it gains only 4 - 7 seconds. Should it then be adjusted based on the high activity gain an then be slow on a regular day?

But that said an since it sems that nobody else is experiencing the same variance i assume there is someting wrong with my Rolex and that this is not a typical trait of an mecanical movements or typical Rolex behacviour. It will go back to my AD next week...

[Brushpup]

Originally Posted by Kallagtunet

I understand what you say and that it is the average over 24 hous over several days that is the baseline for adjustment but what i really do not understand is how the RSC are going to adjust based when the variance due to activity levelmis so is so big. On a days where i have high activity level a running session and much walking it will gain 20 - 25 seconds but on a day on a regular office day witout any exerzise it gains only 4 - 7 seconds. Should it then be adjusted based on the high activity gain an then be slow on a regular day?

But that said an since it sems that nobody else is experiencing the same variance i assume there is someting wrong with my Rolex and that this is not a typical trait of an mecanical movements or typical Rolex behacviour. It will go back to my AD next week...

They will just regulate it. Not based on your activity, that isn't possible or needed. If your timing/monitoring is correct, there is something wrong with the watch. There should be very little variance, no matter your activity level.

[Kallagtunet]

Originally Posted by Brushpup

If your timing/monitoring is correct, there is something wrong with the watch. There should be very little variance, no matter your activity level.

Yep, that is unfortunately what I think also. To bad to have this experience after waiting to buy a new Rolex for a long time...

Have just had a 35 minute jogging trip and before i started it was + 33 seconds after the trip it was + 47 sec... AD here I come!

Hopefully but not likely I will not part with it for long and hopefully they will not mess it up with scratches or dust or whatnot while tying to fix my brand new watch...

[FNFZ4]

My DJ is about 1 sec per day. My Sub Serti is about the same too.

[Brushpup]

Originally Posted by Kallagtunet

Yep, that is unfortunately what I think also. To bad to have this experience after waiting to buy a new Rolex for a long time...

Have just had a 35 minute jogging trip and before i started it was + 33 seconds after the trip it was + 47 sec... AD here I come!

Hopefully but not likely I will not part with it for long and hopefully they will not mess it up with scratches or dust or whatnot while tying to fix my brand new watch...

I feel for ya. Been there with a BNIB watch from an AD. They will sort it out, and hopefully pretty soon back to you. Good luck.

[padi56]

Originally Posted by Kallagtunet

Yep, that is unfortunately what I think also. To bad to have this experience after waiting to buy a new Rolex for a long time...

Have just had a 35 minute jogging trip and before i started it was + 33 seconds after the trip it was + 47 sec... AD here I come!

Hopefully but not likely I will not part with it for long and hopefully they will not mess it up with scratches or dust or whatnot while tying to fix my brand new watch...

When they put your watch on the timing machine they will test it in 5 positions and then regulated it if needed.Now thats if there is nothing else wrong with watch internally.Now they can only regulated to the beat rate to what the machine records while testing.If then your watch is still the same while doing activity like running jogging etc only answer is not to wear the watch while doing this type of activity. But its a strange one but its got to be something simple but get it back to AD or direct to RSC after you ring them first.

[JGlo66]

I have this problem with my Exp II, which I bought from an AD in 2007. Until earlier this year, it was almost spot on for days at a time. (Now its about +6/day). Unless I kept it on when going for a run. It gains 10-20 sec during my 2-mile/20-min jog. It happened again tonight. I once asked a watchmaker about it. He wasn't surprised; said it was something about the winding mechanism continuing to wind up at high rate after reaching capacity.

[mmmk604]

My watches run -1s/day to +4s/day...are you sure you are timing yours correctly?
Seems way off for a new GMTIIc with the Parachrom Blu Hairspring.

[submariner66]

Originally Posted by padi56

First you cannot test any watch the way you are testing it say over a few hours of activity.To do a accurate test first wind the watch fully 40 crown turns clockwise.Then sync watch if you have a "quartz" watch that will do for this test,after sync just wear as normal.Check time once daily with same setting source over 5 full days, then average out the lose or gain over those five days,but take your watch off at night.If results are still way off the COSC spec a AVERAGE of -4 to +6 seconds over any 24 hour period your watch needs checking by RSC.

A digital quartz watch?

[zion_rasta]

My GMT IIc is for show. I look at the time on my phone :p

[zion_rasta]

Make sure your GMT IIc is wound properly and that the crown is screws on properly.

If it is not, the watch will have a hard time keeping time. That is my experience with it.

[padi56]

Originally Posted by submariner66

A digital quartz watch?

Don't make any difference a quartz watch is a quartz watch whether digital or analogue. And will be far more accurate than any mechanical only watch and accurate enough to test any mechanical watch.

[Brushpup]

Any update on the repair?

[MJK737]

I've noticed this also with my automatics with lower end movements. I'm pretty sure when your swinging your arms while running the balance wheel is not making a complete arc. The shorter arc of the balance wheel will speed up the watches amplitude thus making it run faster. After your run the balance wheel should swing normally thus settling down and becoming more accurate. Rolex uses shock protection and screws on the balance wheel to somewhat prevent this. Perhaps that is your issue? I run with my 16750 all the time and its pretty bang on. I did notice is sped up about 5 sec. once but that was a one time event. I use the USNO Master clock to check accuracy and I do so often. Bottom line is it's a mechanical watch and there's going to be some fluctuations.