patrick_y
[PuristSPro Moderator]
33528
Good question.
It's actually not that small. At around 8mm, for a modern movement, it's actually quite large. The only reason why you think it's small, is because it looks small, relative to the very large movement. The movement is really quite thin, at 2mm, but the movement diameter is extremely large at 36.6mm!!! That's a huge diameter movement! Which is difficult to fit inside a 40mm case! The movement does use a 21,600 VPH frequency. Pretty normal by today's standards. And an 8 mm balance wheel is also very normal. A Patek Philippe 240 caliber balance wheel is probably 8-9mm, also 21,600 VPH frequency. Just the movement is smaller so it does look larger relative to the rest of the movement.
Comparing Bulgari BVL 138 Calibers.
I asked Google to compare the BVL 138 720 and BVL 138 721 movements. This is the summary as compiled by Google Artificial Intelligence. Accuracy score 100%. Zero hallucinations. Much of the reference material is from WatchProSite articles. Bravo Google! B...
That's great! I hope you're wearing it often!
Mine is unfortunately not winding consistently. As you may remember, my watch often will stop at 2AM or 3AM despite having worn the watch for 20,000 steps each of the 2-3 days prior. So, when I wear mine for a week straight, I often have some small proble...
Why do balance wheels tend to be so small these days?
...it seems like they used to be much larger. Is a larger size no longer necessary because of modern materials?
Good question.
It's actually not that small. At around 8mm, for a modern movement, it's actually quite large. The only reason why you think it's small, is because it looks small, relative to the very large movement. The movement is really quite thin, at 2mm, but the mov...
In this case I will buy it...
...but here is a 30-255 PS from a Patek 6119. The balance wheel seems tiny to me. It looks incomplete somehow... ...
Modern movements are higher frequency.
Higher frequency means that they oscillate at a higher frequency. This one is 25,200; which is much higher than 21,600. Keep in mind, watches typically oscillated at 18,000 vph. You'll notice that modern movements oscillate faster but have smaller and lig...
Notice how small the Chopard 1.96 is...
Generally, what you're going to see is larger companies with A LOT OF MONEY and SCALE are going to go towards 28,800 VPH. This higher beat does cost a lot more money in R&D (but can save money in the short run), and it also costs a lot of power reserve! B...
This makes sense and addresses what I asked...
...but aesthetically, I am not a fan of tiny balance wheels : )
Large balance wheels can be very accurate...
Large balance wheels can be very accurate. They have more mass (thus higher inertia). They're slightly harder to shock because they're larger. BUT, once they are shocked, they take forever to gain their sync and recover from that shock. This is due to the...
If you would still have the choice between these 2
I guess EVERYBODY would pick the first, right ?? To e all these changes done by the manufacture have only 1 goal and that is ' make is cheaper to produce so OUR profit margin get's bigger'
Hmm. I think that depends...
So, I'm one of the people who have been a little unlucky with the 1st gen movement. When I wear this watch as my only watch, the winding mechanism doesn't wind very well, and even on fairly active days, mine doesn't build up the reserve. So let's say hypo...
Thanks for this great comparison.
I have the original movement and never had any complaints about the accuracy and winding efficiency. And I certainly value the movement for its beautie....which was one of the main reasons for me to buy the watch! Best, Gerard ...
You should see the gigantic metal box to the Sejima!
It came in a giant metal box that had the little circle pattern on the outside. It's in the left side of the photo. ...
Good to know!
I definitely have experienced some winding problems. It's not noticeable if you are at home and you switch watches often and/or you leave the watch in a watch winder (the watch will wind on a winder, just not on your wrist). But it is noticeable if you're...
From another forum…
…I posted the following a while back: UPDATE: Thanks to a very helpful Bvlgari BVL 138 manufacturing video from WatchAdvisor, the latest iteration (gen. 2) of the calibre seems to be an upgrade, at least in terms of performance and reliability, because ae...