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Rep Rolex GMT movements explained

Mrgkman

Known Member
13/8/18
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Sorry, I referenced Puretime’s movement description on their VRF Batman. Thanks for clarifying.

And thank you for the bracelet/correct dial info! You’re the man KJ.

Might be a little too much work for my taste.

Does anyone have any good feedback on owning/wearing a GMT rep with one of these “timebomb” movements? How long are these things lasting before they fail?


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Dissemination

Renowned Member
15/6/19
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Sorry, I referenced Puretime’s movement description on their VRF Batman. Thanks for clarifying.

And thank you for the bracelet/correct dial info! You’re the man KJ.

Might be a little too much work for my taste.

Does anyone have any good feedback on owning/wearing a GMT rep with one of these “timebomb” movements? How long are these things lasting before they fail?


Sent from my iPhone using RWI

How long they last is directly proportional to how lucky you are :p

But for real, there is a sticky about GMT movements and how to set them. In theory, if you follow the directions and keep your watch on a winder, it could last you a while.

But imo you would be better off going with one of these new movements even w/out replacing rep parts with gen parts. Cus at least its repairable if it busts.
 
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Mrgkman

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If anyone spots a TD selling these, please let us know!


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KJ2020

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If anyone spots a TD selling these, please let us know!


Sent from my iPhone using RWI

Send the link from TSWATCH to any TD. If the watch is released any TD can get it.
 

rabl253

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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.


I don't understand what this means. When you say it's slaved to the hour hand does that mean in some of the DG movements, it's always at a fixed offset and you can't change the offset between the GMT hand and the hour hand?
 

KJ2020

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I don't understand what this means. When you say it's slaved to the hour hand does that mean in some of the DG movements, it's always at a fixed offset and you can't change the offset between the GMT hand and the hour hand?

Correct, except that in the ones where it's slaved there is NO offset. On these models, the GMT hand is simply an AM/PM indicator and a second timezone can only be observed by rotating the 24 hour bezel to create a visual, but not a physical hand offset. This was the case with every 4-digit gen and two 5-digit models, the 16750 and 16700.

On Rolex GMTs, the GMT hand completes one full rotation in 24 hours. It is geared differently from the hour hand, which will complete two full cycles for every one cycle of the GMT hand. So at 7 o'clock, the GMT hand may indicate 7 or 19. This is not a GMT offset.

DG2813 - GMT hand is slaved to the hour hand

DG3804 (DG2813 variant) - GMT hand is independently adjustable via crown, allowing you to observe a third timezone by also using the rotating bezel.
 
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CaptTango1

Banned member, the goat does not approve
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KJ2020 This is a great post KJ!!! If you had two brand new GMT's in your hands, fresh off the press... which one would you pick and why? and would you do any part swaps in between the two to make it even better?

1. Noob GMT Pepsi
2. ARF GMT LN
 

KJ2020

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KJ2020 This is a great post KJ!!! If you had two brand new GMT's in your hands, fresh off the press... which one would you pick and why? and would you do any part swaps in between the two to make it even better?

1. Noob GMT Pepsi
2. ARF GMT LN

Working on one now bro and it involves your old blue dial watch, haha. But in the meantime you can see some combos from this guy

https://forum.replica-watch.info/forum/rolex-tudor-replicas/8784895-arf-gmt-blro-pepsi-video-review
 

romeospadre

Looking Around
17/4/20
1
4
3
Colchester
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
RWG.jpg


15565143374068.jpg


4 digit - 1675
5tZ3P.jpg


5rg7J.jpg


5 digit - 16710
Gen-BP-1-Medium.jpg


5tKmL.jpg


6-digit - 116710 LN (Black), BLNR (Batman), 116713 LN (Two-tone)
5t3cQ.jpg


5thCR.jpg


6 digit - 126710 BLNR (Batman), BLRO (Pepsi), 126711/5 CHNR (Root beer)
5t2S8.jpg


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.
5rg7J.jpg


5tKmL.jpg


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


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).
esvlj.jpg


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.

5tOSb.jpg


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.

5ttgn.jpg


5tQo3.jpg


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.

5tkHJ.jpg


5XAvb.jpg


hLMlt.jpg


Summary Chart
.
4 digit5 or 6 digit
Hour hand on bottom Date change by jumping hour hand
New DG3804ICHSCHSunevaluated
ETA 2824ICHSCHSTIMEBOMB
VR3185/SH3186n/aCHSsuperclone
GMT hand on bottom Quickset date change
DG2813CHSICHSnon-independent GMT
DG3804CHSICHScheap, reliable
ETA 2836CHSICHSSAFE 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

Thank you, very informative!
 
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shortlegs

Active Member
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Hello friend, can you edit away your post, to exclude quoting the whole post? You don't need to quote the whole post just to show gratitude to KJ...
Appreciate your action. Thanks man!

I was about to post a scathing reply to him. You are obviously a nicer person than I, ha..
 

WildString46

Known Member
9/1/20
157
62
28
Weast!
I may be looking for a unicorn, but does anybody know of a 5-digit case set that would fit a VR3186?

I think the potential problem I may run into is the 3186 movement height which is 0.5 mm taller than 3135 (where there are quite a few options for 5-digit case sets).
 

John Abel

Known Member
15/5/20
127
84
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UK
Great post. It would be even greater if it included the Explorer models that also have a GMT hand
 

Nigeld

Horology Curious
2/4/20
8
6
3
Uk
Thank you for one of the most helpful and instructive bit of advice I have read on this site
 
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