GMT hand watches - usage review

[conx 0]

I do a lot of overseas travel due to my work which means being able to know the time in two different time zones is very important to me. Because of this GMT watches have become a bit of obsession and I have tried various different movements and designs in the hope of finding the perfect solution (for me).

 

I thought I would share my thoughts and experiences after trying various different movements and watches….

 

There seem to be 3 main variations in operation of GMT watches:

 

1. GMT hand which can be set independently and moves continuously when setting. (Typically 21J GMT watches and some A2836/Swiss 2836 GMT watches)

2. GMT hand which can be set independently, but jumps in hour increments when setting keeping it in sync with minute hand (ETA 2893-2 and some A2836/Swiss 2836 GMT movements)

3. GMT hand which cannot be set independently – the time zone is changed by a jumping hour hand. Sometimes referred to as a “True GMT” movement. (Gen Rolex GMT, Omega GMT and Seiko 8F56 quartz)

 

I have tried all three variations and these are my experiences with pros and cons for each.

 

21J movement – Rolex Explorer II rep

 

 

I purchased this rep Explorer II with a 21J movement from WBK. In use I set the main dial to the local time zone of wherever I am and then the GMT hand to the time in London. (I do this with all the other GMT hand movements below...).

I chose the 21j movement based upon feedback here that the 21J movement was the best and most reliable GMT movement (However, I believe many of the A2836/Swiss 2836 GMT movements available also operate in the same manner). In practice it has been rock solid, but the challenge I had was getting the GMT hand to be accurate to the minute hand. The GMT hand moves continuously at the first crown click point. What I found this means is that unless you change the time at the hour, it is difficult to adjust the GMT hand to point accurately at the correct point on 24 hour marker scale on the bezel. Another drawback is that you have to change the hour and minute hands to set local time. If like me you have accurately set your watch you will lose your minute hand accuracy when setting your new time zone as you hack the movement and move both the minute and hour hands. But the biggest drawback for me was the GMT hand not being easy to set accurately.

 

Pros:

Rock solid 21J movement

 

Cons:

Continuous GMT hand adjustment makes accurate setting difficult

Having to hack and move the minute/hour hands to set local time means you can lose accuracy.

 

 

21J movement – Rolex GMT II-C rep

 

 

To try and solve the problem with the continuous movement of the GMT hand, I picked up this GMT IIc from Timeshops. Although it is the same movement as before, the rotating bezel provides a solution to my GMT hand accuracy dilemma. What I do with this is accurately set the GMT hand to my local time zone once. Then when I need to change time zones, I set the main dial to the new time - the GMT hand stays nicely in sync when doing this. I then adjust the bezel so the GMT hand is showing the time in London. For example, when travelling to Dubai which is four hours ahead of GMT, I set the watch to Dubai time and simply move the bezel forward 4 clicks (i.e. the triangle would point at 2 o'clock) and the GMT hand is now showing London time. Works great – no need to set or move the GMT hand at all!

 

Pros:

Rock Solid 21j GMT movement

Rotating bezel - makes setting 2nd time zone easy

 

Cons:

Continuous GMT hand adjustment - as above

Having to hack and move the minute/hour hands to set local time means you can lose accuracy.

 

 

ETA 2893 movement (jumping GMT hand) - Debaufre GMT gen

 

 

I picked this up on eBay as I wanted to try a true Swiss movement with jumping GMT hand. This has a movement where the GMT hand adjusts in hour increments. This means that it is always accurately in sync to the minute hand. This works really nicely as I can just set the main dial to the local time and then move the GMT hand to London time and know that the GMT hand will be accurately set and in sync with the minute hand. The only drawback I can see with this type of movement is that as with the others, having to set the main dial by moving the hours and minute hands means you can lose the accuracy of your watch, especially as you are typically doing this on a plane with no accurate time reference available.

I believe some rep A2836/Swiss 2836 GMT movement reps can operate this way, but I couldn’t find a TD who could confirm this with any confidence.

 

Pros:

High-beat 28,800bph movement

Jumping GMT Hand

 

Cons:

Having to hack and move the minute/hour hands to set local time means you can lose accuracy.

 

 

Seiko 8F56 "True GMT Hand" movement - Pulsar PM5001

 

 

This watch, while not an automatic, has what some call a “true GMT” movement. What this means is that the GMT hand always moves in sync with the minutes hand and you can move just the hour hand independently of the other hands. The gen Rolex GMT-IIc and gen Omega GMT movements work this way. In use, you set the local time by moving the main dial hour hand. The GMT hand always remains pointing at your home time. The benefit of this approach is that you can easily move between time zones without compromising the accuracy of your watch as you don't move the minute hand at all and the watch doesn't hack when moving the hour hand so even your seconds accuracy is maintained. In use this has been the most logical watch to set and also the quickest and easiest. I don't know of a rep that has a movement that works this way (although some of the CHS Rolex reps may), so you are limited to something like a quartz pulsar/Seiko with an 8F56 movement like this, or an expensive Rolex or Omega gen if you want this type of operation. I also believe that Seiko have now discontinued this movement. I haven’t tested if their new Kinetic movements with GMT hand operate in this way (but again I believe they do).

 

Pros:

Ease of time zone setting

Logical to use

Maintains watch accuracy

 

Cons:

Not many movements work this way.

Most expensive solution (assuming gen Rolex/Omega)

 

 

In summary, if I had to choose I would select movements in this order

1. True GMT (either Seiko 8F56 or Rolex/Omega)

2. Jumping GMT hand movement or 21J movement with rotating bezel

3. 21J movement

 

In other words the exact opposite to the order I bought mine in!

 

Finally, none of the above watches/movements is able to accurately show a 2nd time zone which is offset by half an hour. India is an example of this, which is 5.5 hours ahead of GMT. Fortunately I haven't been sent to India (YET !)

[jeffw69 0]

Very cool.

I have a GMT Pepsi with swiss mvmt and ICHS.

I don't really wear it or use the function much.

 

Thanks for the review.

[myaz 3]

Great review. Thanks for taking the time to put it together.

[King 0]

Nice summary. I'd personally love to see a reliable rep with "true GMT." I think some of the older Rolex GMTs with the "correct hand stack" operated in this manner, but they were notoriously problematic. I'm not a fan of the "jumping" GMT hand at all, and so I stick with the 21Js and a7750s (both reliable GMT movements), although I also have a Rolex GMT with a clone ETA (which is not so reliable ...).

[conx 0]

I agree about the reliable rep with true GMT, if there was movement that worked the same as the Rolex GMT at a realistic price these would sell like hotcakes. The way that movement works just seems so much more logical to me.

 

 

I have seen posts over at RG where Angus at Puretime is saying that a clone of the Rolex GMT movement is coming. If this is the case (and it was reliable and not a timebomb) the GMT 11c would be the ultimate rep for me.

[honeybear 0]

Yeah, one really needs a reliable GMT movement built from the ground up. My understanding is that even if we ignore the reliability issues with the CHS modification, it is still problematic, since the quickset on the 12 hour hand should be tied in with the date change as well, but apparently the date change on the CHS models is still tied in with the 24 hour hand.

 

I have a cheapie Seiko Perpetual Calendar based on the 8F56 movement, and it's actually quite interesting to look at when quicksetting the 12 hour hand on Feb 29. When I moved the 12 hour hand past midnight, the date changes from 29 to 1 automatically, and if I shift it back before midnight, the date would go backwards from 1 to 29. The seconds hand seems to freeze while the date shift occurs, but then speeds up until it catches up with real time, very interesting to play with.

[mianos 0]

I also have the Seiko Sportura with the 8F56. It's hard to go past the sub 10 seconds per year timekeeping and the very handy GMT function (and that's not mentioning the 100 year perpetual calendar). The 1 hour hand jump is such a good system when changing timezones.

[Daywatch 4]

Very interesting read. Thx for posting. Which one do You use today?