Great power reserve test of new Yacht-Master II caliber 4161.

[Mystro]

I always like to do a initial power reserve test of a new watch. It can be very difficult because you can’t wear the watch for the test but because of our snow storm, I opted to do the test knowing I would be doing a lot of snow removal. Here are my notes of the test:

12/15/20 7pm full wound +0.0 resting 12UP
12/16/20 +1.0 @ 9:30am......+1.50 @ 3:45pm +2.0 @ 8:30pm
12/17/20 +2.0 @ 12:30pm.... +2.0 @ 7:30pm
12/18/20 -1.0 @ 9:30am. -4.0 @ 3:30pm. -6.0 @ 5:15pm. -9.0 @ 6:15
Stopped 6:46. 71 hours and 46 minutes

Rolex states 72 hours approximately for the caliber 4161 so I am right on spec. Now I have a base line for future test to gage the main springs health. What I found the most impressive with this movements test was how long the movement stayed well within COSC long into its mainspring wearing down. As most know accuracy is only measured at the top of its mainspring fully wound but after that initial 24h, amplitude will get lower and that will also change its accuracy. For this YMII, I am in Swiss COSC for 68 hours and “ Superlative Chronometer” for 60 hours which may be a record for any of my Rolex watches. :happyanim:

As a reference of some of the other new Rolex movements I have tested.
Rolex DSSD JC 126660 movement 3235 total:h70:05
Rolex SD43 126600 movement 3235 total: h70:23
Rolex CHNR 126711CHNR movement 3285 total: h71:44
Rolex BLNR 126810BLNR movement 3285 total: h72:40

To do this simple test: Wind the watch fully and set the time to a atomic clock. Set the watch down to where you can see the time but not have to touch the watch. Keep track of the watch daily until it stops. This will give you a mainspring check-up and reference point. Notice where in the power reserve you start to see the accuracy start to fall off.
Why this matters:
Now if you drop or notice issues with your watch, you can do this test again and compare if you may have any mainspring damage. If all of a sudden you are getting 17 hours power reserve, you know your mainspring has broken. Think of it as a EKG of your watch.

[sleddog]

Interesting results.

[Mystro]

Originally Posted by sleddog

Interesting results.

Thanks Rob,

I have done a basic time keeping test if you let the Chrono run over night. I “think” it slightly slows down the watch only by 0.50 seconds over a 12 hour duration which is next to nothing. In the future, I may do a power reserve test with the watch on the scope with Chrono running as well as keep track of its time keeping the entire time. This is purely for fun and watch nerd data.