GMT evolution

[jasper]

I'm a newb - a Omega Speedy man, but I'm peretty sure there's either a SS Sub or a GMT in my near future.

My question regards the evolution of the GMT. I think I understand that the GMT and GMT had different functionality and hence have the evolutionary naming, but why is the GMTIIC, which seems significantly different than the GMTII not named GMT III ?

Also - why is the 50th anniversary Sub called an LV - Luminaire Verde?

Thanks for helping a newbie -

[mike]

jasper,

The difference between the GMT-MASTER and the MASTER II is basically one of functionality.

MASTERS have the 12 and 24 hr. hands synced together, whereas the MASTER II series allows for the decoupling of the 12 and 24 hr. hands.
The latest GMT II reference, the 116710, continues in this tradition of using the "jump hour feature as did the 16710 it replaced.
True the watch features many upgrades, but the function of the movement remains the same.

LV stands for Lunette Verde---Green Bezel.

[jasper]

Thanks Mike - uh oh - can you clarify how the 12 and 24 hour hands can be decoupled. Don't they have to be synched in order to maintain the time difference?

[jasper]

Never mind - this link tells me all I need to know.


http://www.rolexforums.com/showthread.php?t=23681

Cheers and thanks.

[mike]

Originally Posted by jasper

Thanks Mike - uh oh - can you clarify how the 12 and 24 hour hands can be decoupled. Don't they have to be synched in order to maintain the time difference?

Sure,

The GMT-MASTER series as typified by the 1675 used a system whereby the 12 and 24 hr. hands worked in unison with each other. That is they were "synced" together. The 12 hour hand made two revolutions around the dial while the 24 hr. hand made one.
Reading a second timezone was normally done off the bezel or one had to reset the watch when arriving in a new zone and set the bezel to "home time" (which could be a real pain.)
The 1675 was also a slow set date watch which could also be a pain if setting the 12 hr. hand to local time for short periods.

Rolex gave the MASTER series a bit of a boost circa 1979-80 with the advent of the reference 16750. While still using the synced 12 and 24 hr. hand concept at least the 16750s were the first to use a true quick-set date feature.
This called for another position on the crown---Pos 1. to wind, Pos 2 to set the date, and of course Pos. 3 to set the hands.
Normally a second zone was still read off the bezel.

With the advent of the reference 16760 GMT-MASTER II Rolex brought us to where we are today with a movement featuring a "Jump-hour" feature.
Now when set to position 2, one can advance the 12 hour hand in one hour increments (or move it back) with no effect on the 24 hr. hand.
Now we had the capability of reading local time off the dial while maintaining contact with "home" off the bezel. The system works quite well for those going in and out of multiple timezones and as the minute hand is not affected (keeps moving) accuracy is maintained.
Additionally because of this feature the bezel can be used to track a third timezone by simply rotating and resetting the triangle to 12 to bring us back to home time.

If there is a down side to the "Jump hour" it is that it negates a true quick-set date feature. On MASTER II (16760, 16710, 116710) the hour hand must be advanced twice around the dial to set the date.

A visual guide,

http://www.movements.dk/doc_gmt_01-02_gb.html

1675,



16750,



16760 and 16710,



116710,

[diamonddatejust]

nice read!!

[FlyingMoose]

If it's still confusing, here's a nice video demo:

http://youtube.com/watch?v=76RAJWQoosE

[jasper]

OK - the GMT II function is now clear - thanks for the video! But do I understand correctly that the original 1675 function required the wearer to adust the bezel in order to "set" the second time zone?

Sounds like the GMT II function is a quantum leap forward....and I guess that answers my very original question of why the names changed when they did.

I get it now. Thanks guys.

So....can I get a GMT II with the Pepsi bezel, or is that GMT I only? Are the bezels on the GMT II always interchangeable? What about the GMT IIc ?

I hope and expect to make a decision soon about my next watch, and first Rolex. I really like the sub, and especially the LV. But I'd rather light my hair on fire than go anymore than 1 or 2 metres underwater, so the raison d'etre of the sub would be wasted on me...not really my style to waste good resources.

I'm heavily leaning towards a GMT at this point because of the time zone and 24 hr functionality, which I would actually use. I understand now that the GMT is waterproof to 100m, which is more than enough for me in the shower and occasional dip in the wading pool with my kids.
But I think the small crown might bug me. So that means a GMT IIc....

Thing is I need a *bit* of colour to justify my next purchase since I have a prfectly good, and very *ahem* sexy Omega Speedy pro which is all black and steel.

I could live with a normal (Mark I) GMT II though. I suppose the small crown might only be a minor annoyance. I suppose also I should go try one or two on.

By the way, this is the third (or is it the fourth) internet forum that I'm a member of now. The other two are Porsche forums, and like those forums the vibe on this one is real mature and respectful. Lot's of tech know how, and not so much pomp/crap. I was on a Subaru forum for a while....nuff said.

Thanks for helping out.

[FlyingMoose]

As far as I know (and hopefully one of the more experienced members can correct me if I'm wrong):

With the GMT II, they kept the rotating bezel and added the separate hour-hand setting, so you can actually have 3 time zones (though one of them you'll have to sort of guess at the numbers). You can set the 12-hr hand on one, the 24-hr hand on a second, and the bezel on a third.

The GMT II has the Coke and Pepsi bezel, but as far as I know the GMT II c only has black. I'm not sure about the GMT I, but it's probably hard to get anyway. I don't think they're interchangable between the I, II, and IIc.

I'm a member of so many forums I've lost count (and have even started and run a couple)...

[johan]

welcome to GMT II ... I got into the same brain drain last month trying to pin into GMT II vs GMT II C... I end up buying GMT II due to its interchangable bezel and slightly smaller size ( got a small wrist)

[Ken Cox]

I have a question about the bezel insert.

I have a 1986 16760 "Fat Lady," which I recently had restored, and I had the bezel insert replaced, but with the bezel insert original to that year.

However, my conversations with the watchmaker who did the restoration somehow led me to believe I had other genuine Rolex options than the red and black bezel of the '86 GMT Master II.

Did I?

I like the originality of the red and black, and would have chosen that anyway, but did I really have a choice?

[mike]

Originally Posted by Ken Cox

I have a question about the bezel insert.

I have a 1986 16760 "Fat Lady," which I recently had restored, and I had the bezel insert replaced, but with the bezel insert original to that year.

However, my conversations with the watchmaker who did the restoration somehow led me to believe I had other genuine Rolex options than the red and black bezel of the '86 GMT Master II.

Did I?

I like the originality of the red and black, and would have chosen that anyway, but did I really have a choice?

Ken,

Certainly you do. While the 16760 was originally issued only with the RED/BLACK insert, any color combination foe a GMT II will fit.--It MUST be an insert for a GMT II though, inserts for the GMT-MASTER will NOT fit due to a difference in the inner and outer diameter.

[mike]

Originally Posted by jasper

OK - the GMT II function is now clear - thanks for the video! But do I understand correctly that the original 1675 function required the wearer to adust the bezel in order to "set" the second time zone?

Sounds like the GMT II function is a quantum leap forward....and I guess that answers my very original question of why the names changed when they did.

I get it now. Thanks guys.

So....can I get a GMT II with the Pepsi bezel, or is that GMT I only? Are the bezels on the GMT II always interchangeable? What about the GMT IIc ?

I hope and expect to make a decision soon about my next watch, and first Rolex. I really like the sub, and especially the LV. But I'd rather light my hair on fire than go anymore than 1 or 2 metres underwater, so the raison d'etre of the sub would be wasted on me...not really my style to waste good resources.

I'm heavily leaning towards a GMT at this point because of the time zone and 24 hr functionality, which I would actually use. I understand now that the GMT is waterproof to 100m, which is more than enough for me in the shower and occasional dip in the wading pool with my kids.
But I think the small crown might bug me. So that means a GMT IIc....

Thing is I need a *bit* of colour to justify my next purchase since I have a prfectly good, and very *ahem* sexy Omega Speedy pro which is all black and steel.

I could live with a normal (Mark I) GMT II though. I suppose the small crown might only be a minor annoyance. I suppose also I should go try one or two on.

By the way, this is the third (or is it the fourth) internet forum that I'm a member of now. The other two are Porsche forums, and like those forums the vibe on this one is real mature and respectful. Lot's of tech know how, and not so much pomp/crap. I was on a Subaru forum for a while....nuff said.

Thanks for helping out.

You got it on the timezone function of the GMT-MASTER.

As to bezel inserts, here's the breakdown:

Original GMT-MASTER,
Options--RED/BLUE, BLACK.

GMT-MASTER II
Options--RED/BLUE, BLACK, RED/BLACK

NOTE: Bezel inserts MUST be for the correct reference number.
Due to a difference in the inner and outer diameter, Inserts between a MASTER and MASTER II will NOT fit.

The ceramic insert is unique to the reference 116710.


Oh, and there's NOTHING wrong with the Speedmaster!!



A comparison of inserts,

Black--16750, R/BLUE--1675, R/BLACK--16710



Ceramic,



16710 vs. 116710,

[Dan Pierce]

Mike,
Your knowledge and pics are a real valuable resource her.
Thanks as always.

jasper,
Join the 4 hand club. Any version of the GMT is well worth it.



dP

[frostie]

Originally Posted by FlyingMoose

If it's still confusing, here's a nice video demo:

http://youtube.com/watch?v=76RAJWQoosE

I've seen that video it's a good review and it can teach you how to use the gmt function.

[equinox]

The video is very usefull as a guide to us all.

[jasper]

Thread revival!

Still looking for the perfectwatch. I was convinced I wanted a GMT II but after seeing a really nice 1675 for sale recently I've been thinking....

A question about crystals and open lugs.

Did the 16750 come with a plastic crystal ? I know the 1675 did, and the 16710 didn't but...

I also notice the 1675 and 16750 came with open lugs. Did any of the GMTII models come this way as well ?

And ok - a bonus question....where did the 16760 fit in? Was this the "transitional" model? What does this mean again?

Thanks

[f16570]

Yep join the 4 hand club and get the slightly left of centre choice.
This BAD BOY.

[mike]

Originally Posted by jasper

Thread revival!

Still looking for the perfectwatch. I was convinced I wanted a GMT II but after seeing a really nice 1675 for sale recently I've been thinking....

A question about crystals and open lugs.

Did the 16750 come with a plastic crystal ? I know the 1675 did, and the 16710 didn't but...

I also notice the 1675 and 16750 came with open lugs. Did any of the GMTII models come this way as well ?

And ok - a bonus question....where did the 16760 fit in? Was this the "transitional" model? What does this mean again?

Thanks

Answers.

Indeed the 16750 (both with the original matt dial and later with the gloss with WG surrounds) were issued with acryllic crystals. The ONLY GMT-MASTER to be equipped with a sapphire crystal was the reference 16700--circa 1988-99.

Yes. Both the reference 16760 and earlier 16710 Master II came with lug hole cases.

The reference 16760 was the first GMT-MASTER II to be fitted with the "jump hour" movement allowing the 12 and 24 hr. hands to de-link. The 16760 was fitted with a 3085 movement, upgraded to the 3185 in the 16710.

Most do not consider the 16760 a "transitional" as it was a completely new watch. "Transitional" is a term usually used for the reference 16750 which faetured the first fast beat 3xxx movement in a GMT while (at least initally) keeping the traditional matt dial and always the acryllic crystal.

[SPACE-DWELLER]

Excellent posts, as usual, Mike!

Thanks for sharing!

[frostie]

Here's another GMT evolution photo

[mike]

Originally Posted by frostie

Here's another GMT evolution photo

Cool shot!

Best I can do is this,

[Prince]

Originally Posted by mike

...Best I can do is this...

Yeah, and the kicker is...THEY'RE YOURS!!!!

[frostie]

Nice pic Mike i've seen it before Thanks for sharing

[Tools]

Go get yourself a GMT II.... it's the last of a breed....

[cmr]

brother, all i can tell you is that i love my gmt2c, for me it is a wonderful piece of workmanship and is a absolute delight to wear and look at!!!!!!

[CPCC]

GMT is a keeper

[jasper]

Thing is like the acrylic crystal and the open lugs....

Frostie, it would be helpful if you could identify each of the watches in your photo.

Mike...the reference to 16700 has caught me off gaurd. I thought I was getting until then. You say it was produced 1988 through 1999. That seems like a long run. Which watch is this then?

[bwalkerVintage]

Originally Posted by jasper

OK - the GMT II function is now clear - thanks for the video! But do I understand correctly that the original 1675 function required the wearer to adust the bezel in order to "set" the second time zone?

Sounds like the GMT II function is a quantum leap forward....and I guess that answers my very original question of why the names changed when they did.

Granted I have a GMT, but in reality, using the bezel for a quick time change is easier than changing the hands. Aside from the decoupling ability for the 24 hour hand, the GMT II adds the ability to track a third time zone and the other "quick" features (all of which make changing thigs easier when you have to). That being said, I have never really needed to track three time zones even though I do travel to foreign lands.

I say all this so you won't be afraid of vintage GMTs because they are awesome watches with a rich history. Also, The GMT IIs are really nice as well. I don't think you could go wrong in either case.

Good luck!

[veefour]

Is there a GMT IIc with a red fourth hand, or only green?