Spring Drive (SBGA413) - Long Term Accuracy

[gozoner]

After getting my Grand Seiko SBGA413, in large part because of the spring drive technology, I decided to measure the long term accuracy over a full year. I'm 20 weeks in and thought I'd describe the results so far. (During this 20 week period I found myself in Scotland for 10 days; refused to change the time to the local time zone.)

I'm impressed with the accuracy; but, after searching posts on this site, I've found others reporting 0 or 1 second after 3 months?!

Date (weeks)	  Error (sec)    Rate (sec/week)	Rate (sec/day)
06/13/2023 ( 0)	     0		
07/18/2023 ( 5)	    +5                1.0                  0.14
08/22/2023 (10)     +7.5              0.75                 0.107
09/26/2023 (15)     +11.5             0.77                 0.11
10/31/2023 (20)     +15.1             0.755                0.108

It gets easier to measure the error as it grows; but I've started using a G-Shock chronometer with >1/10 second resolution recently - which probably explains the first error of +5 being larger and second error increase of 2.5 being smaller.

Total error is +15 seconds over about 4 1/2 months which is well below the stated accuracy of 15 seconds per month. Should I be disappointed?

I'm keen to keep the test going for a full year - which will mean handling daylight savings time by presetting the error when changing the time. We'll see how the watch handles the frigid winters.

Cheers.

[minute_man]

Hi, congrats on the beautiful cherry blossom and welcome to the forum.
I think your accuracy is fine. My SBGE245 gains about 2,5" a month. Both are well within GS's claimed accuracy. I wouldn't be surprised to see outliers on either side of the spectrum though. I know first hand just how spoiled can someone become with the GS SD accuracy. Don't let that mess with your ownership experience. Enjoy your watch.

[PBJ1925]

Seems well within specs, enjoy your 413, it's a beauty.

[Andad]

Originally Posted by gozoner

After getting my Grand Seiko SBGA413, in large part because of the spring drive technology, I decided to measure the long term accuracy over a full year. I'm 20 weeks in and thought I'd describe the results so far. (During this 20 week period I found myself in Scotland for 10 days; refused to change the time to the local time zone.)

I'm impressed with the accuracy; but, after searching posts on this site, I've found others reporting 0 or 1 second after 3 months?!

Date (weeks)	  Error (sec)    Rate (sec/week)	Rate (sec/day)
06/13/2023 ( 0)	     0		
07/18/2023 ( 5)	    +5                1.0                  0.14
08/22/2023 (10)     +7.5              0.75                 0.107
09/26/2023 (15)     +11.5             0.77                 0.11
10/31/2023 (20)     +15.1             0.755                0.108

It gets easier to measure the error as it grows; but I've started using a G-Shock chronometer with >1/10 second resolution recently - which probably explains the first error of +5 being larger and second error increase of 2.5 being smaller.

Total error is +15 seconds over about 4 1/2 months which is well below the stated accuracy of 15 seconds per month. Should I be disappointed?

I'm keen to keep the test going for a full year - which will mean handling daylight savings time by presetting the error when changing the time. We'll see how the watch handles the frigid winters.

Cheers.

Hi,
+15s over 4.5 months = +3.3s/m.

The stated accuracy can’t be 15seconds/month.
You mean 15 seconds/year?

[minute_man]

Originally Posted by Andad

Hi,
+15s over 4.5 months = +3.3s/m.

The stated accuracy can’t be 15seconds/month.
You mean 15 seconds/year?

That's a SD movement, Eddie, not a quartz. So 15' / month is about right iirc.

[Little machines]

Welcome to the forum! Beautiful time piece congratulations!!! Specs look correct.

[Andad]

Originally Posted by minute_man

That's a SD movement, Eddie, not a quartz. So 15' / month is about right iirc.

That was my point Basil - why should Gozoner be disappointed with 3.3s/month?

[minute_man]

Originally Posted by Andad

That was my point - why should at be disappointed with 3.3s/month?

Ahh got it now It's easy to get spoiled by the SD accuracy. I know I am.

[gozoner]

Originally Posted by Andad

That was my point Basil - why should Gozoner be disappointed with 3.3s/month?

Not disappointed; I knew the specification prior to purchase. Just here seeing people reporting way better - so confirming in-practice vs specification. Thanks!

[WatchEater666]

I've had two spring drive equipped watches.

SBGE275 which tends to gain about 2 seconds every 2 - 3 weeks.
SBGE255 which gained about 2 seconds a week??? I think. Cant really remember.

[Dip14]

My snowflake loses only 1 second a week, so 4 seconds per month. I have had it for 15 months now.

[alllexandru]

I don't know how you can live with such deviance from atomic time

[gtnator]

All SD movements are highly accurate, but the newer one is even more


Sent from my iPad using Tapatalk

[Locust]

Best movement on the planet

[watchnwine]

Mine is about 1 second per week... by the time I need to change the time for daylight savings or advance the month on a 30 day month, the accumulated error isn't even enough to worry about. It is one of my favorites in the box and I find I wear it more than almost any other.

Enjoy - you'll need to adjust it before the error matters too much.