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Rep Rolex GMT movements explained

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    Rep Rolex GMT movements explained

    So you want to buy a rep Rolex GMT Master and you are confused by all the different models and the hand stacks and the movements and the endless conflicting information. Well, this will hopefully clear up some of the confusion and help you make more informed choices on your purchases.

    I will focus mainly on the rep differences in this post, but if you want to learn more about the history and the evolution of the models, see this link. You can read up here about different variations in each model like insert options, dial indices, SELs, lug holes, etc. That is not the focus of this post.

    http://www.gmtmasterhistory.com/

    MODELS
    First let’s talk about models. I’m restricting these listings to the most common reps, there are additional variations in the 5 and 6 digit series. Here are some examples of the most common models.

    4 digit - 6542




    4 digit - 1675




    5 digit - 16710




    6-digit - 116710 LN (Black), BLNR (Batman), 116713 LN (Two-tone)




    6 digit - 126710 BLNR (Batman), BLRO (Pepsi), 126711/5 CHNR (Root beer)


    HAND STACK
    CHS = Correct Hand Stack
    ICHS = InCorrect Hand Stack

    The 4-digit gen models have the GMT hand on the bottom of the hand stack. 5 and 6 digit gen models have the hour hand on the bottom. Rep movements can have the hand stack correctly configured, or incorrectly configured depending on what movement is used with which model. Note that a certain movement can be correct for one model and incorrect for another model with regard to hand stack. The hand stack is only as important as you make it. The GMT and hour hands are only near each other for about two hours a day, otherwise it’s not that noticeable to many.

    Here are pics of a 1675 and a 16710. If you zoom in you can see that both have the GMT hand on the bottom. From the discussion above, we know that this is CHS for the 1675 and ICHS for the 16710.




    Here is a pic of an hour hand on the bottom of the stack. This is CHS for 5 and 6 digit models.


    Note that BP/GMF uses a GMT hand hole surround that is larger than the hour hand hole surround beneath it. Don’t let that stop you from ID’ing both these watches as CHS (hour hand on the bottom).


    MOVEMENTS
    This is the main focus of this post, to help members differentiate among the various movements available for rep Rolex GMTs. Many TD sites list the movements incorrectly and it is ultimately up to you to know what you are buying. You need to become skilled in identifying two aspects of the watch pics you see on a TD website - the hand stack and the movement. If you correctly ID both of these, you will know for sure what you are buying despite what the site information may say. It is very easy to do this, I will show you how. We previously saw how to ID whether the hand stack is CHS or ICHS, next we will see how to ID the movements.

    Movements can be broken into three main groups - DGs, ETAs, and Superclones.

    DG MOVEMENTS
    DG movements for GMTs will be either a 2813 or a 3804, depending on whether or not the GMT or hour hand is independent. Many cheaper DG GMTs will not have an independent GMT hand, it is slaved to the hour hand, but on a 24 hour rotation cycle. On these models, the bezels must be used to observe a second time zone. Note that the gen 4 digit GMTs and two early 5 digit gen models (16750 and 16700) did not have an independent GMT or hour hand.

    Look at the TD movement pics to ID the DG movements. They are easy to ID. Almost always has blue screws, big blue rotor screw, simple looking movement. These movements are the cheapest ones you can buy in a rep and although they are pretty reliable and will likely last a while, they are not easy or cost effective to service. If one fails it is usually better to just replace it. So ID your hand stack and your movement to know what you are buying.



    Plain DG2813 - no GMT feature

    GMT DG2813 - has an extra gear for a non-independent GMT hand. Sometimes referred to as 21j or 23j.

    If the DG movement has an independent GMT or hour hand, it is a DG3804. Usually referred to on TD sites as a DG2813 or sometimes even as a 21j or 23j (Nembo, for example). You'll know it is really a DG3804 by the independent GMT or hour hand. Aftermarket vendors list them properly if you have to buy a replacement movement.

    DG3804 with independent GMT hand on the bottom - is CHS for 4 digit Rolex GMTs, ICHS for 5 and 6 digit Rolex GMTs.

    New DG3804 with jumping hour hand on the bottom - is ICHS for 4 digit Rolex GMTs, CHS for 5 and 6 digit Rolex GMTs. Note that TD sites still refer to this movement as a DG2813, but will state "hour hand moves like gen" or something similar. They function just like the ETA 2824 movement, with a jumping hour hand. These movements have not been out long enough for their reliability to be adequately evaluated. They are unique and only available from a TD.

    ETA MOVEMENTS
    These movements still account for the majority of rep Rolex GMTs sold. They will either be an A2824 (jumping hour hand on the bottom) or an A2836 (independent GMT hand on the bottom). Many people will simply refer to these ETA movements as CHS or ICHS, but remember that this depends on what model the movement is in.

    4 digit gen models have the GMT hand on the bottom, so

    A2824 - is ICHS for 4 digit Rolex GMTs, CHS for 5 and 6 digit Rolex GMTs. This is the TIMEBOMB movement! It has a jumping hour click spring that can easily break which will keep your hour hand from working. These movements are unique and only available from a TD.

    A2836 - is CHS for 4 digit Rolex GMTs, ICHS for 5 and 6 digit Rolex GMTs. This the SAFE BET ETA movement. These movements are more easily repaired or replaced from aftermarket sources.

    Look at the TD movement pics to ID the ETA movements. The key to identifying an ETA movement is the autowind module and crown wheel. Once you learn to recognize those, it is easy to tell it is an ETA movement. The hand stack will tell you the rest.





    Important notes: TDs will often list these movements as A3186, or A3285 or “Asian superclone”. Do not be fooled! Learn to ID the movement as an ETA clone, and know what you are buying. Remember that while the A2824 movement is the timebomb movement, it can be made to last longer if you treat it carefully and properly. Minimize use of crown position 2 and use a winder to keep the date close to correct.

    How to set your timebomb movement

    SUPERCLONE MOVEMENTS
    These movements are true superclones of the gen 3185/6. VRF makes the “VR3185”, ARF makes the “SH3186”. These are two new, revolutionary movements based on the VR3135 and the SH3135. The VRF has a clone jumping hour spring based on the gen 3185, the ARF has a clone jumping hour spring based on the gen 3186. Both movements seem to be a generational leap ahead in terms of capability and reliability, some may prefer the VRF because of the more robust jumping hour click spring.

    Gen jumping hour click springs compared

    The movements are similar in appearance and easy to identify. They both will only be CHS, since so far they are only available in 6 digit models.







    Summary Chart
    .
    4 digit 5 or 6 digit
    Hour hand on bottom Date change by jumping hour hand
    New DG3804 ICHS CHS unevaluated
    ETA 2824 ICHS CHS TIMEBOMB
    VR3185/SH3186 n/a CHS superclone
    GMT hand on bottom Quickset date change
    DG2813 CHS ICHS non-independent GMT
    DG3804 CHS ICHS cheap, reliable
    ETA 2836 CHS ICHS SAFE BET
    `
    Happy hunting, GMTs are Great!

    Some additional links

    New DG3804 GMTs

    How to set your TIMEBOMB movement

    Why the TIMEBOMB movements fail

    Swap your TIMEBOMB to a SAFE BET movement

    New ARF vs VRF GMTs

    VRF Batman released
    Last edited by KJ2020; 28-12-19, 00:15.
    We are all related in time since time is relative to us all.
    GMT Movements Explained
    BP Rolex 16710 GMT Full Review VS Gen
    Swap your CHS movement to ICHS - possible?
    The Fantasy Watch Thread
    Noob GMT's poor bezel design
    Ceramic insert paint mod
    GMF releases 3186 GMTs



    #2
    Another great contribution here KJ. Thank you !

    Comment


      #3
      Great post. Thank you for your contribution to the community!

      Comment


        #4
        Great job as always

        Comment


          #5
          You knocked it out of the park! Thanks!


          Sent from my iPhone using RWI

          Comment


            #6
            Wow thank you, that's a biblical post!
            Plase make it sticky.

            Envoyé de mon ELE-L29 en utilisant Tapatalk


            Last edited by mrsullivan; 22-12-19, 06:09.

            Comment


              #7
              Amazing info. No one should have any more questions about the gmt movements. This thread covers it all.

              Comment


                #8
                Great, KJ!


                Sent from my iPhone using Tapatalk
                "Did mcbigmac stole a watch from me?" -oascom
                founder and member of The Official RWI Planet Ocean Club and the RWI Seamaster Club.
                siggy by WingNut

                Comment


                  #9
                  What a fantastic Xmas gift for every RWI GMT lover. Thank you Kj! Seasons greetings, and I wish you a successful and rep-rich 2020. May all your movements be smooth and well regulated.

                  Comment


                    #10
                    Quite a Christmas present for the forum Kj2020.
                    Very informative.

                    Comment


                      #11
                      Epic post. Thanks for this!

                      Comment


                        #12
                        Great as usual. Thanks bro!


                        Sent from my iPhone using RWI

                        Comment


                          #13
                          Thanks for the amazing clarity ! Should be required reading for all who are new to this hobby! Like me!!


                          Sent from my iPhone using RWI

                          Comment


                            #14
                            Thanks man. This is great. I’ve been scouring the gmt threads asking these very questions for weeks but there are so many threads, it’s hard to keep track of where I asked it, which movement I asked it about and then it get febuzzled when people chime in with conflicting opinions. It’s been maddening. But this is awesome. It’s like a central resource for all the information and it’s a good place to ask questions about the movements instead of in the individual threads.

                            And I didn’t know the 4 digit GMT’s and some of the t digit didn’t have independent hour hands. Look at how far we’ve come. I mean imagine when that came out, how exciting it must have been for watch nerds of the time?! I mean we freak out because there is a clone of a good movement. I can only imagine.

                            I do have one question though. On a gen Rolex GMT Master II, the date can set forward and backwars, correct? That is if it is 2 am and you set the time back to 10pm, the date can go back 1 day instead of having to go forward 30 days again. Is there a clone movment that does this too?

                            I thought i read read about this as a feature a while ago but I haven’t really been able to get an answer. I may have just inferred this by misreading/misinterpreting “the hour jumping feature” but I’m not 100% sure.

                            This is fvcking awesome. Thanks again, buddy.

                            Comment


                              #15
                              Originally posted by Hazing View Post
                              Thanks man. This is great. I’ve been scouring the gmt threads asking these very questions for weeks but there are so many threads, it’s hard to keep track of where I asked it, which movement I asked it about and then it get febuzzled when people chime in with conflicting opinions. It’s been maddening. But this is awesome. It’s like a central resource for all the information and it’s a good place to ask questions about the movements instead of in the individual threads.

                              And I didn’t know the 4 digit GMT’s and some of the t digit didn’t have independent hour hands. Look at how far we’ve come. I mean imagine when that came out, how exciting it must have been for watch nerds of the time?! I mean we freak out because there is a clone of a good movement. I can only imagine.

                              I do have one question though. On a gen Rolex GMT Master II, the date can set forward and backwars, correct? That is if it is 2 am and you set the time back to 10pm, the date can go back 1 day instead of having to go forward 30 days again. Is there a clone movment that does this too?

                              I thought i read read about this as a feature a while ago but I haven’t really been able to get an answer. I may have just inferred this by misreading/misinterpreting “the hour jumping feature” but I’m not 100% sure.

                              This is fvcking awesome. Thanks again, buddy.
                              Really the hour hand is what is independent on gens, but the phraseology of independent GMT hand often arises in blogs, etc. and is not incorrect - the GMT hand is not dependent on the setting of the hour hand, hence it is "independent". Of course the gen GMT hand is not independent of the minute hand, like it is in some rep movements.

                              The two 5 digit gens that did not have independent hour hands (16750 and 16700) are GMT Masters (I). They had movements 3075 and 3175, both of which had the quickset date feature.

                              Gen 5 digit GMT Master II's with movements 3085/3185/3186, all gen 6 digit GMTs, and all rep movements with the hour hand on the bottom must change the date with the jumping hour hand or crown position 3. Hour jumping date changing can be done either forward or backward on these newer gens, and on both the new VRF and ARF superclone movements. I believe this is also true for the new DG3804 movement with the hour hand on the bottom. I will have a couple of those in hand soon.
                              Last edited by KJ2020; 23-12-19, 05:52.
                              We are all related in time since time is relative to us all.
                              GMT Movements Explained
                              BP Rolex 16710 GMT Full Review VS Gen
                              Swap your CHS movement to ICHS - possible?
                              The Fantasy Watch Thread
                              Noob GMT's poor bezel design
                              Ceramic insert paint mod
                              GMF releases 3186 GMTs


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