*Picture credit AskMeAgain*
~History~
Rolex GMT Master History and Reference Pictoral (Part 1) by eVojlib
Rolex GMT Master History and Reference Pictoral (Part 2) by eVojlib
The History of the GMT by Debellum
The Rolex GMT-Master wristwatch was originally designed in collaboration with Pan Am Airways and issued by the airline to their crews on transcontinental long-haul flights. ("GMT" in the name stands for Greenwich Mean Time). The watch has a convenient capability that was unique at the time as it enabled the crews to have GMT or another second time zone displayed. GMT is the time zone that is required for all aviation planning, weather forecasts, schedules and other paperwork. In addition as Inertial Navigation and Global Positioning System technologies did not yet exist, and aircraft were out of range of normal radio navigation beacons during transoceanic flights, an accurate GMT time source was essential for use with specialist sextants for astronavigation (obtaining geographical position by relative angles of the horizon, the sun and other stars). In fact the very first “Marine Chronometers” (the predecessors of more modern mechanical watches) were specifically developed for use in astronavigation on ships during the 18th century.
The second time zone on the watch also proved a great help to crews for managing jetlag and for communications home when abroad. It is this capability that has made them very popular with businessmen and other travellers. They have also been particularly popular with NASA and military pilots and many soldiers and sailors who often require GMT or a second time zone.
In the early 1980s the Rolex GMT-Master II was released (although production of the original version continued alongside it until the late 1990s). Although the watch looks almost identical it uses a movement that has the additional capability of a quickset hour hand that can be adjusted to local time without stopping the seconds or disturbing the minutes and 24 hour GMT hand. As the watch continues to feature the rotatable bezel it is now able to display a third time reference.
The Rolex GMT 24 hour hand feature has been adopted by many other watch manufacturers and is now a relatively common feature. However nearly all of these watches use an ETA movement that is operated slightly differently from the Rolex GMT-Master II design (the 24 hour hand is quickset rather than the local hour hand) and whilst perfectly usable, it is a slightly less convenient design for pilots and regular travellers but very suitable for those staying at home and wishing to track a time zone in another country (e.g. Telephone calls for business or relatives abroad). Omega are one exception as they operate in the same way as the Rolex GMT-Master II.
Although the original Rolex GMT Master was only available in Stainless Steel, as it was conceived as a functional, work watch, Rolex have been making luxury versions in both mixed steel and gold and all gold since the 1970s and there are even exotic variations that incorporate elaborate designs that include precious stones. All variants have significantly increased in their purchase cost relative to inflation and are now often regarded as high luxury or status symbols. In spite of this they still make a very accurate and robust work watch that is very well suited to its original design purpose and with their all metal construction, shock proofing and water-resistance they still remain popular amongst pilots today.
The 50th anniversary model has a green "GMT" hand (forth hand) and the words GMT MASTER II on the face are also in green. Green has traditionally been used by Rolex to denote watches that have been in continuous production for 50 years. The updated GMT Master II also has the new in house produced hairspring, dubbed by Rolex as the "Parachrom hairspring". The new hairspring is made of a new Non Ferromagnetic alloy which has a distinct blue colour. The hairspring is reported to be less susceptible to magnetic fields and more resistant to shocks, leading to a more accurate timepiece. The watch has been nicknamed the GMT II C to distinguish it from its predecessors.
~Movements~
Rolex WIKI page - All the basics
Please see the above link for information on the current movements found in GMT Master I and II replicas.
DG3804
Asian Clone 2836-2 (CHS and ICHS)
Asian Superclone 2836-2
ETA 2836-2 (CHS and ICHS)
SW220 (Sellita)
A3186
~Handstack (CHS/ICHS)~
When referring to handstack we are talking about the ordering of the hands on the movement. On all regular 3 hand movements the Hour hand is placed on the movement first, followed by the Minute hand and finally the Seconds hand.
In Vintage GMT models (1675) this has the additional GMT hand first (as above pic), followed by the others in succession. With the 16750 onwards this is different.
Hour Hand / GMT Hand / Minute Hand / Seconds hand - (as below)
There are two variations of replica GMT movements. Firstly you have the DG3804. This is a low beat movement with native GMT function (meaning it is a purpose designed GMT movement). This is low beat 21,600 BPH and is closest to the beat rate of the 1675. Its handstack is also accurate to the 1675.
The modified Clone 2836 (or ETA 2836) has an aftermarket addition of gearing to allow the GMT hand to work. This is a high beat movement of 28,800 BPH and is accurate to modern Rolex movements. The handstack is innacurate for representing anything other than the 1675. When this movement is used in 16750 models onward it is referred to as an Incorrect Hand Stack (ICHS).
There are modified movements out there with the Correct Hand Stack (CHS) as per the gen movements in the 16750 models onward. These are rarer than the ICHS movements and are prone to breaking down. As a result they are not recommended.
Rick914 had this to say on the modified 2836 movement in a discussion found here:
Movement for CHS GMT? by gw4k
GMT-Master II 116710 LN with Correct Hand Stack by rarebear
Are GMT IIc's unreliable?! by Low Note
~How does the genuine GMT function work?~
Jumping Hour Hand: On genuine Rolex GMT movements they have what is described as a jumping hour hand. When changing the time the movement remains unhacked (seconds hand continues to move) and the hour hand moves in 1 hour increments. This allows the wearer to change the local time zone on the main time keeping hands without altering the time keeping of the watch. The GMT hand will continue to follow the original time zone.
Jumping GMT Hand: On replicas we have it backwards to the genuine. The GMT hand is tied to the Date setting position of the movement. This means that when we counter clockwise rotate the crown the GMT hand will 'Jump' one hour. If we adjust the time the GMT hand will 'follow' the timekeeping of the main hand set. This means that to change time to local, and keep GMT hand to home time we have to set the main hands to local and then change the GMT hand forward or backwards to 'home' time.
NOTE: The jumping GMT hand is present on the ETA 2893 GMT and modified Clone/ETA 2836 movements. The 21j DG3804 movements GMT hand is infinitely adjustable and does not 'jump'.
~Coke / Pepsi / Lunette Noir~
These are the terms used when describing the bezel insert on the GMT master.
~Spiderweb dial~
For more information on this please see this thread:
Spider Webbing / Crazing Explained Via Images.. by justloungin
GMT Master
~16750~
Production Period: 1981-1988
Model Name: Rolex GMT Master
Caliber: 3075, 28800A/h, hacking, quickset
Pressure proof to 100m/330ft
Bracelet: Oyster 78360, Jubilé 62510
Glass: Acrylic crystal
Indexes: Tritium
The 16750 followed the 1675, introducing the quickset feature. With this change, the order of the hands got changed:
1675: GMT/Hour/Minute/Second
16750: Hour/GMT/Minute/Second
Two different variants of the dial:
Matt, without white gold indexes - rare.
Glossy, with white gold indexes (identical to the newer GMTs). Rolex switched the dial during production (approx. serial 9XXXXXX / 1986). This dial was first introduced without 'Date'-imprint, later versions show this imprint. During service, many matt dials got replaced by glossy ones.
Other Variants:
Ref. 16753 steel/yellow gold (Oysterbracelet 78363, Jubilébracelet 62523) aka "Root Beer GMT"
With black dial and insert:
Ref. 16758 yellow gold (Leather or Oysterbracelet 7206/8, Jubilébracelet 6311/8); sapphire crystal
~16750 Replica Availability~
Some points to note:
The 16750 is the same case as the 1675
Early models had matte dial + applied lume markers
Early models were Oyster Perpetual
Early models had the same hand stack as the DG3804 and ETA 2836-2 modified GMT movements
Later models had gloss dial + white gold markers
Later models were Oyster Perpetual Date
Later models have a different hand stack as the DG3804 and ETA 2836-2 modified GMT movements
Most of the 'vintage' replicas available are based on the 1675, and not the 16750.
Are there any Franken capable 16710 or 16750 GMT II's currently available?? by correctime
Rolex 1655 to 16750 Birthday Project Build - Pictorial... by justloungin
*Picture credit AskMeAgain*
GMT Master II
~16760 aka Fat Lady aka Sophia Loren~
Production Period:1983-1988
Model Name: Rolex GMT Master II
Caliber: 3085, 28800A/h, hacking, quickset (24-hour-hand)
Pressure proof to 100m/330ft
Bracelet: Oyster 78360, Jubilé 62510
Glass: Sapphire crystal
Indexes: Tritium
The Ref. 16760 is the first GMT Master II.
It is nicknamed Fat Lady because of it's extra thick case.
First GMT with white gold indices borders and sapphire crystal, steel was the only option.
Was only offered with the red/black bezel, which was also a new combination.
With the new caliber 3085 the 24-hour hand became Independently adjustable. The seconds hand only stopped when the crown was pulled all the way out -> accurate time could be kept while setting the watch.
Extra large crown guards.
Even more interestingly, the 16760 GMT-II boasted an extra-thick case, some .5mm thicker than its predecessor, as well as a thicker bezel & crown guards. This has led to the affectionate nicknames “Fat Lady” and “Sophia Loren” in a nod to the 16760’s zaftig proportions. One can see in this comparison with the 16660 Sea-Dweller just how thick the original GMT-II’s case actually was:
Produced only until 1988, the short-run 16760 was replaced by the much longer running ref. 16710 GMT-Master II. Not only did the 16710 sport a new caliber of movement (the identically functioning cal. 3185), but it had also lost weight and returned to more slender, GMT-like dimensions.
~16700~
Production Period: 1988-1999
Model Name: Rolex GMT Master
Caliber: 3175, 28800A/h, hacking, quickset (direct)
Pressure proof to 100m/330ft
Bracelet: Oyster 78360 and 78790 (Oysterlock starting 1989), Jubilé 62510
Glass: Sapphire crystal
Indexes:
Tritum up to U-Series 1997: T<25 dial
Luminova starting 1998: Swiss dial (variant: Luminova on T<25 dial)
1988 the Ref. 16700 replaced the Ref. 16750. The Ref. 16700 was cheaper compared to the Ref. 16710 which got introduced at the same time.
The caliber 3175 (same functions as the 3075) had still the non-independant hourhand which was the main difference between the Ref. 16700 and the Ref. 16710.
New introduced with this watch:
Sapphire crystal
White gold indexes (altough some predecessors (Ref. 16750) were also already equipped with these).
New case
Date-wheel has vintage open numbers until 1992/1993.
Only available in Stainless Steel.
Bezel colors:
BLRO, Blue/Red aka Pepsi (bleu/rouge), (Bezel 315-16700-6)
LN, Black, (Bezel 315-16700-1)
~16710~
Production Period: 1989-2007
Model Name: Rolex GMT Master II
Caliber: 3185 (late models with 3186), 28800A/h, hacking, quickset (24-hour-hand)
Pressure proof to 100m/330ft
Bracelet: Oyster 78360 and 78790 (Oysterlock), Jubilé 62510
Glass: Sapphire crystal
Bezel: Anodized aluminum, 120 clicks
Indexes:
Tritium (until 1997): T<25 dial
Luminova (1998/99): Swiss dial
Superluminova (2000-2007): Swiss made dial
The Ref. 16710 replaced 1989 the Ref. 16760 featuring a new, but identical functioning caliber and a slimmer design.
Variant: Luminova on a T<25 dial (1998)
Evolution:
1997/2000: Tritium -> Luminova -> Superluminova
2000: Solid end link bracelet indroduced (SEL).
2003: Laser crown introduced.
2003: No holes case starting (late Y-series).
2007: New certificate (plastic/credit card size) introduced (Z-series).
Late 2007: Caliber 3186 instead of 3185 (late Z-series and the M-series).
Available with three different bezels:
Red/Black aka Coke (Bezel 315-16760-7)
BLRO, Blue/Red aka Pepsi (bleu/rouge), (Bezel 315-16700-6)
LN, Black (lunette noire), (Bezel 315-16700-1)
Other variants:
Ref. 16713 steel/yellow gold aka Tigerauge (Tigers Eye) (Bezel: 315-16713-5 or 315-16718-1); Oysterbracelet 78363 and 78793 (Oysterlock), Jubilébracelet 62523
GMT Master II Tiger Eye by pcsam
Ref. 16718 yellow gold (Bezel 315-16718-3); Oyster bracelet 7206/8 and 78798 (Oysterlock), Jubilébracelet 8386/8
~16710 Replica Availability / Eyecandy and Information threads~
Modding a noob GMT II The Original and Best thread by BKLM1234
The most accurate option at the moment is a custom build using the 16570 Explorer II replica as a base and adding on a TW best bezel assembly.
3 GMT Masters: 1675, 16710, 116710 by sneed.12
Making a gen style 16710 case out of a 16570 case and TW bezel assembly by BKLM1234
Franken GMT Master II by GlennRyuen
Gen-style 16710 with CHS, reliability update by sneed.12
Rolex GMT Master! by Maw (lots of discussion)
Explorer II to 16710 GMT white dial
An older case set that is no longer in production is the BKLM1234 'Transformer' Noobfactory GMT.
Modding GMT II by BKLM1234
Comparative review: BK Transformer and Noob GMT/Explorer Hybrid by sneed.12
GMT Master II Ceramic
~116710 LN~
40mm as per genuine
Solid mid link bracelet with SEL
Real Ceramic bezel insert
24 click Bi-Directional bezel
Incorrect Hand Stack
Sapphire crystal with no AR cyclops
*Picture credit Puretime.co*
~116713 LN~
40mm as per genuine
Two tone 18k plated
Solid mid link bracelet with SEL
Real Ceramic bezel insert
24 click Bi-Directional bezel
Incorrect Hand Stack
Sapphire crystal with no AR cyclops
*Picture credit Puretime.co*
~116718 LN~
40mm as per genuine
Full gold 18k plated
Solid mid link bracelet with SEL
Real Ceramic bezel insert
24 click Bi-Directional bezel
Incorrect Hand Stack
Sapphire crystal with no AR cyclops
*Picture credit asian7750.com*
40mm as per genuine
Full gold 18k plated
Solid mid link bracelet with SEL
Real Ceramic bezel insert
24 click Bi-Directional bezel
Incorrect Hand Stack
Sapphire crystal with no AR cyclops
*Picture credit asian7750.com*
~Bi-colour ceramic bezels~
Up until Basel World 2013 the bi-colour GMT Master was a fantasy piece imagined by the rep makers. This is now a reality but probably not what everyone was expecting. Up for release at some point soon is the 116710BLNR;
New GMT master from 2013 Basel by hurk
Also available from the replica factories is a bezel combination that is not available (yet) from Rolex. The Pepsi and Coke configurations.
~Serti Dials / Diamond Bezels / Pro-Hunter~
Rolex offers a large amount of extra options as standard. Diamond dial markers, diamond bezel inserts, jewel encrusted bracelets and cases. There are so many options, far too many to list here.
Another customising house for Rolex is Pre-Hunter. Usually focusing on PVD / DLC coating and customisation of dials, inserts, hands etc.
~Eyecandy / Modification and Reference threads~
pilworx 116710LN GEN BEZEL BUILD by Pilworx
Gen bezel and crystal GMT IIc by sneed.12
116710 GMT II Mods by Goin6633
DIY The pilworx Penultimate Platinumizing Procedure
Reviewing Puretime GMT-Master II 116710 LN with Correct Hand Stack by miamiboy
GEN Rolex GMT Master II ceramic vs noob rep by watchfaker
Rolex GMT II C V2 and V3 comparison by guru
My new GMTc Coke! by Ruprekt
RLX GMT MASTER II CERAMIC BEZEL REF 116710 vs GEN!!! by Precious Time
Ceramic gold bezel too yellow by dmacnz
GMT-Master II 116710 LN with Correct Hand Stack by rarebear
Picked up my first gens - 116710 and 116520 by watchfaker
New GMTIIc V3 - Review by seifert
Review of ROLEX GMT Master II 116710 Ceramic ETA 2836-2 ICHS by By-Tor
Rolex GMT MASTER II 116713 Modded by ryanwayer
116718 incoming from Lay - please input by thisismynick
Piece of Junk or desirable beauty? (116718) by donaldejose
Contributers to this WIKI:
I would like to thank the following people for contacting me and adding to this WIKI page.
AskMeAgain
justloungin
Pilworx
