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Replica "faux" GMT movement FAQ & tutorial

By-Tor

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16/3/06
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4tRnH6l.jpg

G.M.T = Greenwich Mean Time


I decided to write this quick guide, because there still seems to be lots of confusion about the GMT movements. Besides the real GMT movement, like ETA 2893-2, there are three kinds of "faux" GMT movements in replicas, 2 based on ETA 2836-2, one based on Asian 21J movement.

The first one is the "correct hand stack" modification, which mimics the genuine GMT movement, i.e the "hour hand adjustable" watch. This modification has the GMT hand placed above the hour hand on the stack. The factories have developed this modification specifically for Rolexes, GMT Master II & Explorer II.

On this modification the date change follows the GMT hand, unlike the "wrong" hand stack modification, which makes the date change to follow the hour hand. (Technically the "wrong" hand stack version is just a standard ETA movement where the GMT hand has been attached to the main hour hand with a double sized rotor (that makes the full turn 2x slower.))

The "correct hand stack" modification acts like the real GMT movement, and it allows you to set the hour hand independently without stopping the seconds hand. When you set the crown into the 2nd position, only the hour hand moves in one hour jumps, while the GMT stays immobile. Like I said, there is no hack signal in the hour hand setup position, and the seconds hand keeps running.

Good example of a replica like this is the Explorer II ("correct hand stack model"), which I have reviewed HERE and HERE.

Below is a picture of the correct hand stack on my Explorer II:

QLnlTTb.jpg

However this modification might be unreliable, which is why I don't recommend it. Ziggy explains the potential technical problems with this modification in his movement review section. The link is HERE.


There is also another "faux" GMT movement, which is widely used on replicas. It's the "wrong hand stack" 2836-2 version.

Replica snobs look this movement down their noses, because it doesn't act like the "real" GMT movement. In this modification it's not possible to set the hour hand independently at all, but you set the GMT hand instead. This happens when you unscrew the crown into date set position, and turn the crown anti-clockwise.

epn735s.jpg

The problem with the GMT hand setup is that the GMT hand turns freely and smoothly over the dial, which (supposedly) makes it difficult to set the GMT hand "in sync" with the local time.

In my opinion, this is absolute nonsense. There's nothing difficult to make it sync with the hour hand. Just wait until time is say, 9'o'clock sharp (or before setting the local time, set all the hands at say, '12 sharp manually), and move the GMT hand exactly into the desired xx:00 2nd timezone position.

ZUngzdB.jpg

When you have once set the GMT hand in sync, you don't necessarily have to touch it anymore, ever again (assuming you have a watch like Rolex GMT Master, which has rotating bezel with 2nd timezone hour markers). When you set the time (in the crown position 3) the GMT hand follows along perfectly (and stays in sync). If you want to set your GMT hand to follow some other timezone, you just turn the bezel into the desired position.

If you have a watch like "wrong hand stack" Rolex Explorer II (Exp II has a fixed bezel) or "Bond" Seamaster GMT, you have to manually make it "sync" again with the local time if you want to change the watch to follow another 2nd timezone.


It's also important to understand that the GMT hand takes 24 hours to make "full circle" on the dial. All GMT watches have separate markers for the GMT hand. For example on Rolex GMT Master, Black Omega Seamaster and Explorer II the hour markers for the GMT hand are on the bezel. These 24h markers are probably more natural to use for the Europeans, because it's the European way to tell time (24h system, not AM/PM 12h system).

The Asian 21J version of the "faux" GMT acts exactly the same way.

I have owned several "wrong hand stack" GMT's, and they have been bullet proof and reliable. There's absolutely no reason to avoid this movement. While it's not technically like the real GMT movement, it serves the exact same purpose perfectly and is completely functional as a "GMT watch". The purpose of a GMT watch is to follow the 2nd timezone, and this "poor man's modification" does it perfectly.

WfpNRRb.jpg
 
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ThePadd

Known Member
1/4/16
192
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Good explanation but which Asian movements have the GMT function, as I have a yen to build one of these.
 

chris3007

Mythical Poster
24/8/13
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Good write up, thanks.
BTW: there is on more GMT movement, the 7750, used in many PAM GMT Reps.


Gesendet von iPad mit Tapatalk
 

mikeanh77

Active Member
13/11/18
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i dont know why this post dont get that much attention with all the information available. should be sticky for those who enjoy wearing a gmt rep. sorry if i bring this back up lol


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nothingelse

Active Member
29/10/17
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In my rep journey after Iwc and Daytonas fever I was planning to look at the GMT reps. But I was totally ignorant about these watches. Now I am ignorant the same but a little less. Great informative post.Everyone should read this one before to place a GMT order.


Inviato dal mio iPhone utilizzando RWI
 

Alexccmeister

Active Member
8/11/18
446
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i dont know why this post dont get that much attention with all the information available. should be sticky for those who enjoy wearing a gmt rep. sorry if i bring this back up lol


Sent from my iPad using RWI

Maybe because this post was created in 2008 and since then the rep makers have probably updated the movements several times over. I am pretty amaze how far the replica watch technology has come to (or what we use to call it as fake when owning them in my younger years) The gen-like quality is mind boggling. I am now wearing my rep spectre and am so happy with it.
 

mikeanh77

Active Member
13/11/18
490
267
63
Asia
Maybe because this post was created in 2008 and since then the rep makers have probably updated the movements several times over. I am pretty amaze how far the replica watch technology has come to (or what we use to call it as fake when owning them in my younger years) The gen-like quality is mind boggling. I am now wearing my rep spectre and am so happy with it.

I feel you. I joined rwi pass september and loving it since.
my luck to find the forum. Never imagine there is a strong rep community like this.
also never thought about rep since i think all rep are just crap. Until i really owned my arf sub my mind change totally. Can't beat a good running watch, low price high quality, cheap servicing. Down the road if the watch are scratchy beat up you can just buy a new one. So 10 years you can have a brand new watch again on your wrist lol. Not like a old beat up 40 years old sub that look all scratch up and over polished which service every 5 years or so cost 500usd.
 

Alexccmeister

Active Member
8/11/18
446
108
43
I feel you. I joined rwi pass september and loving it since.
my luck to find the forum. Never imagine there is a strong rep community like this.
also never thought about rep since i think all rep are just crap. Until i really owned my arf sub my mind change totally. Can't beat a good running watch, low price high quality, cheap servicing. Down the road if the watch are scratchy beat up you can just buy a new one. So 10 years you can have a brand new watch again on your wrist lol. Not like a old beat up 40 years old sub that look all scratch up and over polished which service every 5 years or so cost 500usd.

Yup. That's my thought as well.
 

newrepfan86

You're Saying I Can Sell?
29/1/19
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does anyone have any updated info about the reliability of these GMT movements on a CHS like the new noob V9 batman. i am thinking about ordering one and am having trouble finding new info about reliability on them.
 

kolincio

You're Saying I Can Sell?
21/5/18
65
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The problem with the GMT hand setup is that the GMT hand turns freely and smoothly over the dial, which (supposedly) makes it difficult to set the GMT hand "in sync" with the local time.

I'm not sure about this - My GMT watch with modified A2836 clearly jumps the gmt hand by 1hour increments (or rather decrements I guess) when I set it.
 
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Rx4Time

Supporter, Panerai lover
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does anyone have any updated info about the reliability of these GMT movements on a CHS like the new noob V9 batman. i am thinking about ordering one and am having trouble finding new info about reliability on them.

Time bombs...some run fine but a fair number fail.and there's not a lot of options for repair since the movement isn't sold separately and the primary point of failure is a custom spring. I'd avoid it or plan on the start of a project. A SH3135 can be converted to a 3186 by swapping roughly 10 pieces, but at minimum you need a genuine handset. This is roughly a $1k fix to get a reliable movement.