GMT/Daytona Bracelet to a Sub Date... More than you want to know..

[Tools]

We get asked all the time "Can I fit a new GMT IIc Bracelet to my Sub 16610" (OK, it's not always the Sub...but that is the example today)

The short answer is Yes...but with conditions..... and these conditions are a bit different for other watches..

First, let me say that the 78200 bracelet is a direct replacement with the Daytona 78590 except it takes a 2mm spring-bar and the Daytona takes a 1.8mm spring-bar - but they are so close the fit is very comparable. The main difference is in the SEL.. The spring-bar diameter is no small difference... You must use the 2.0mm spring-bar with the 78200 and the 93250, whereas, it simply will not fit through the smaller 1.8mm diameter tube hole of the Daytona 78590... You use the spring-bar for the bracelet...not the spring-bar for the watch !!

Back to the project at hand; a GMT or Daytona to a Sub Date...

The Sub 16610 has an SEL 93250, and the root (thickness of the bracelet where it meets the case side) of the SEL is 4.5mm thick. The GMT 78200 has a root thickness of 5.5mm, so there is more meat on the GMT bracelet; the Daytona 78590 also has a 5.5mm root.....this will make it fit differently.



Inside the two bracelets are somewhat different at the SEL, as mentioned.

The backside of the GMT 78200:


Backside of the Daytona 78590...notice the central angle and blend is very different.


Another thing to note is that the Rolex SEL has two flanges... On the 78200 and 78590, these flanges are quite thick...almost twice the thickness of the typical bracelet SEL:


The flange thickness is interesting because the Daytona and the GMT both have machined lips on the back of the case to accept the thicker flange.. Other Rolex SEL cases have the shallower lip to capture the SEL, including the Sub-Date. Of note is that the Sub 14060 has no flange lip and a Rolex SEL will not fit..

This shows the deeper SEL lip on a Daytona:


Here we see the shallow SEL lip on a 16570. It is the same as the Sub Date 16610:


Either of these bracelets will mate up to a 16610.. Oddly enough though, the Daytona Bracelet, using a 1.8mm spring-bar fits a little high and produces a lip at the top of the lug..

Perhaps this is variable with other samples. It can certainly be filed to fit, and it may not interfere at all..


Both bracelets, due to the larger flange we discussed, and the shallow lip, will not fit flush at the back, but will have a prominent lip.. In use it is not really an issue and extends no more than the early hollow end links:



So.. What have we learned..

It is possible to update your flat channel, hollow center link Sub Date to a more modern solid center link, and billet clasp bracelet. It is a direct replacement. However, the actual fitment is not precise but completely serviceable and can give new life and comfort to an old classic;;

[Tools]

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[B. Doggy]

I still like to original bracelet on my SUB! Thanks for the info though, Larry.

[Perdu]

I can't believe how clean you keep the back of those lugs, Larry. What is the spring bar thickness for the 16710 BTW?

[Tools]

Originally Posted by Perdu

I can't believe how clean you keep the back of those lugs, Larry. What is the spring bar thickness for the 16710 BTW?

16710's use a 2.0mm spring-bar...same as the Sub.. The Daytona, DJ, YM use a 1.8mm spring-bar.

[JJ Irani]

Great info as always, Larry.

So my TT GMT-IIC takes 2 mm spring-bars, my Exp-II and Sub also take 2 mm bars........but my Pt. YM takes 1.8 mm spring-bars......same as the Daytona.

Good to know!!

JJ

[SLS]

Great info Larry!
and BTW, make sure you don't put any scratches on my GMT!
Scott

[JJ Irani]

...............and if any of you ever plan on putting on a Super Jubilee bracelet, remember you will need 1.8 mm thick spring-bars only.

JJ

[Tools]

Originally Posted by SLS

Great info Larry!
and BTW, make sure you don't put any scratches on my GMT!
Scott

,... This is frustrating... I can't take some measurements and do some experiments because I won't take off all this plastic stuff, nor do I want to take a chance to scratch it....

But, you know...once it's actually mine.. off come the plastics, out comes the Scotchbrite...and we will definitely know how thick that case-back is....

[Tools]

Originally Posted by B. Doggy

I still like to original bracelet on my SUB! Thanks for the info though, Larry.

Hey...That's alright... I don't have any issues with folks who just want to own a watch.....

Not everybody makes a hobby out of watches, clocks, and the science horology.........

[mfer]

Thanks Larry, but I'll keep my "inferior" sub bracelet. The lightness actually makes it very comfortable (and I have a IIc also).

I love this kind of info. I'm book marking this.

[RREngr]

Larry, based on what you discussed, my new 116613's bracelet (97203) should fit on most of the GMT family, right? The reason I ask is, with my 116613 on the rubber dive strap it is a shame to have the bracelet sit in the safe. I'd like to get a vintage GMT or GMT II to go with the new bracelet. Is this feasible? Any help would be appreciated, Mike

[jets]

I wanted to try this when I had a 116710 for a while. Too bad I don't have the proper tool yet...