The case size is a tricky number to give the full picture of the watch. Yes, it can tell you how large the watch looks, but it certainly doesn't tell how large or small it will wear on the wrist.
For reference, when you say Rolex Explorer 40 is 1mm bigger than the older Rolex Explorer 39, you'd naturally expect the watch to not just be 1mm bigger in size, but also to wear a little bigger than the Explorer 39 model.
For the same, we look at the lug to lug height of the watch, which is where the picture changes completely and where we have the lug to lug height of Explorer 39 at 47.3mm, the same for the All-New Explorer 40 is only 46.3mm i.e. if you have a narrower wrist, the larger case model Explorer 40 will actually wear better on your wrist, being about 1mm shorter in its length.
I received some comments in my YT video where some viewers stated that the height of the first centre link of bracelet on the new model is greater than the older 39mm model. This dimension actually doesn't matter in terms of the wearability of the size. And while I know some reviewers use this dimension to measure the wrist wearability, I think this is simply an inaccurate way and causes more confusion than any help.
The reason is that regardless of how far the first centre link is from the lugs, on the underside, it sticks straight down before the lugs end, so what you measure externally on the centre links, is merely an outer dimension with the thickness of the bracelet included and it doesn't affect the wrist wearability of the watch.
So the most critical dimension from wearability perspective is the lug to lug and as long as your wrist span is greater than the lug to lug height, IMO, you are covered and don't need to worry about the centre link dimensions, which are simply an incorrect and inaccurate measurement.
The new Explorer 40 also comes with a wider 21mm bracelet and when you wear it, you do see and notice that wider bracelet all the way from the watch case to the clasp, including the clasp itself that is wider by 1mm in the new model.
To avoid confusion, the one on the right is the new Explorer 40.
Lastly, the new Explorer 40 also comes with a glossy and jet back dial, and you dont need to put the watches side by side to see how different the dial is.
You can also check out full length video, with lots of wrist shots, lume shot, and HD and 4K resolution clips on our video companion linked below:
So which one is your pick between the new Explorer 40 vs the older Explorer 39 and why?