The Lemania 5100 movement often had this feature, and I owned a couple L5100 chronograph watches with day/date. I like the 24 hour subdial display in an automatic watch because if the watch were dead and you were winding and setting it, you immediately knew if it was AM or PM without having to manually advance the watch through the twelve to see if it is midnight or noon. For a while in Tucson I also had one of these watches with the 24 hour subdial hand reset by a watchmaker permanently 8 hours ahead of the watch's hour hand giving me a constant second timezone reference (Zulu) (There's no Daylight savings in AZ).

 

I confirm the only movement that makes some sense with the 24h subdial is the 5100, actually it's VERY helpful to set date and day and some of them also have a lumed hand, this is my Sinn:

I also agree that in most chrono movements like the Poljot and Seagull derivates they went with the 24h because easier it's easier to make than a real 12h chrono counter, the Alpha Paul Newman is the perfect example of a chrono that needed to be with 3 registers but they didn't want or could not not develop a real functional chrono.

I also have this:

Here Seiko faced the same problem Alpha had: the original watch was a 3 subdials, the one a 3 o'clock measured the tenth of seconds, but in order to use the new movement they preferred to use the 24h complication as the central hand "sweeps" at 1/5 of seconds...they also used an unusual 1h chrono counter...I must say I kindof like this arrangement.

 

I have a chrono with the same movement found in the Silverstone, and I find the 24 hour sub-dial to be useless. I think if it's going to be there, it should be adjustable and act as a second time-zone.

 

I was just thinking the same thing!

 

That's the Seiko Mecaquartz VK64 movement in that Helgrey, there's a few other microbrands that use this movement and I agree and find the 24 subdial rather annoying. Probably added in to make the dial appear more symetrical. The designers could have simply removed it and make do with a minutes totaliser which would have been better IMO. There's several other examples of chronographs with a minutes totaliser up to 30 mintes but no hours totaliser.

 

Yeah I agree. I know of the movement - it just struck me as weird. Still does. To me, the only function is to provide symmetry, and they probably could have provided symmetry AND something else! Oh well. I like the look of it. It's got it's place.

 

That sounds awesome. The clock in my kitchen is a Seth Thomas radio room clock. I used to have it set to my brother's TZ, but it's too easy for me to do that math. So I have it set to zulu as well. If we didn't do DST here, I'd totally do what you did! But since we do, it would drive me nuts!

Good idea, though

 

Totally agree. Bought a Valjoux 7751 powered watch without doing much research and was gutted that the 24 hour sub dial was a non-adjustable indicator. Ah well, lesson learnt

 

Thanks for the responses, all. At this point, I'm not wearing the Silverstone Helgray (Chrono w/ non-adjustable 24 hour sub dial) anymore, so I'll just move on. If I buy another chrono, I'll think harder about the sub dials. Lesson learned. Perhaps a GMT is a better solution for me. GMT pilot watch, perhaps

 

I was wondering the use of a non-adjustable Sub-dial myself - as I usually know if its day or night where I am!!!

However, like a 24hr - GMT hand it does have a use for Navigation.

It will be sync'd with local time - therefore (in the Northern Hemisphere) point the 24-hr hand to the sun - and the 12/24 hour marker will point North. This saves having to bi-sect the angle from the hour to 12-marker on a '12-hour' watch.

 

Are there pictures??

 

Here's a photo, 'nicked' of the internet - of a 24hr sub-dial - the Seiko V64 Meca Quartz has this feature

 

Useful for a submariner.
Useful those that live in the arctic or antartic areas.
Can be used as a compass pointer.
Handy for shiftworkers sleeping all sorts of hours.
Handy for cavers.

I am sure there are more examples of use.

 

This. Think Rolex Explorer II... from everything I've ever read, it was designed for cavers who wouldn't be able to see the sun for days at a time. This make sense for submarine crews, as well. And there are places at the poles where the sun never sets so AM and PM are not easily denoted.

 

I'd rather have ticking subdial for seconds instead of this feature. Even Junkers/Zepplin stay away form these movements (at least the watches I know of)

So many microbrand bicompax watches seem tainted by this. Triva, Boldr...you name it. There's no ticking second unless chrono is running. Don't owners miss it or do they keep chrono running 24 hrs? Elucidate me ye sirs.