Efficiency of self winding mechanism

[ratty]

Hello

I just want to make an observation on the self winding of one of my 16520 Daytonas.

I’ve been wearing a 1990 /91 era Daytona for the last 5 or 6 weeks and I was interested in how long it would continue to run after I took it off.

The watch has not been serviced for at least 10 years and runs very consistently, if a bit fast. I fully wound it when I put it on and really have not been very active whilst wearing it. As I said above, I wore it for about 5 or 6 weeks non stop, during which time it gained about two and a half minutes, with no more winding then took it off and kept an eye on it see how long it continued to run for. It continued for another 32 hours or so. I can’t remember how long it should run after a full wind, but I was quite impressed that it ran on for so long. I suspect that 32 hours represents about 75% of it’s full capability and I was expecting it to stop before this.

I think this just goes to show how efficient the self winding mechanism in the watch is. As I said, there was not much activity during the period I wore the watch, especially for the two days prior to taking it off, but it appears to have coped very well with sitting watching the TV, driving about three hundred miles the day before and two nights sleeping.


Well done Rolex!

[padi56]

Originally Posted by ratty

Hello

I just want to make an observation on the self winding of one of my 16520 Daytonas.

I’ve been wearing a 1990 /91 era Daytona for the last 5 or 6 weeks and I was interested in how long it would continue to run after I took it off.

The watch has not been serviced for at least 10 years and runs very consistently, if a bit fast. I fully wound it when I put it on and really have not been very active whilst wearing it. As I said above, I wore it for about 5 or 6 weeks non stop, during which time it gained about two and a half minutes, with no more winding then took it off and kept an eye on it see how long it continued to run for. It continued for another 32 hours or so. I can’t remember how long it should run after a full wind, but I was quite impressed that it ran on for so long. I suspect that 32 hours represents about 75% of it’s full capability and I was expecting it to stop before this.

I think this just goes to show how efficient the self winding mechanism in the watch is. As I said, there was not much activity during the period I wore the watch, especially for the two days prior to taking it off, but it appears to have coped very well with sitting watching the TV, driving about three hundred miles the day before and two nights sleeping.


Well done Rolex!

How efficient the self winding mechanism in any automatic watch depends on the the wrist activity of the watch wearer. But on all Rolex automatics if stopped or low mainspring power-reserve, always best to give it a manual wind before wearing.

[brandrea]

Originally Posted by padi56

How efficient the self winding mechanism in any automatic watch depends on the the wrist activity of the watch wearer. But on all Rolex automatics if stopped or low mainspring power-reserve, always best to give it a manual wind before wearing.

[77T]

Originally Posted by padi56

How efficient the self winding mechanism in any automatic watch depends on the the wrist activity of the watch wearer. But on all Rolex automatics if stopped or low mainspring power-reserve, always best to give it a manual wind before wearing.

Agree - that ensures uninterrupted power reserve as the auto-wind assembly performs its function to add power and the movement’s inexorable depletion rate.

I have read elsewhere that efficiency of the assembly requires that the rotor spin between 100 to 180 times to cause the ratchet to revolve once. For very active owners this poses no problem.

The number of mainspring coils also plays a role. For each ratchet revolution, one coil is fully tightened and that is worth approximately 8 hours of power reserve.

72 hours of power reserve means a Daytona should have about 9 coils that can be tightened (either manually or via the auto-wind). Since it unwinds at a rate of one coil per 8 hours, the ~180 rotor spins is just barely keeping pace.

All this means nothing unless you can provide enough wrist motion to increase the number of rotor revolutions. Otherwise you will be living in power reserve debt.

For that reason, most knowledge workers (versus more active careers) should make sure your watch is fully wound by pulling out the crown and start winding.

The TLDR is:



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[ratty]

Originally Posted by padi56

How efficient the self winding mechanism in any automatic watch depends on the the wrist activity of the watch wearer. But on all Rolex automatics if stopped or low mainspring power-reserve, always best to give it a manual wind before wearing.

People are often advised that about 40 complete turns of the crown will fully wind a Rolex watch, do you know or have any idea how many turns of the 'winding weight' in the back of the watch it would take to do the same?

I'm assuming it would require a lot more turns because the size of the weight can not generate anywhere near the torque of a human hand, but I'm curious to know roughly how many.

[77T]

~1,690
+/-10%


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[ratty]

Hi Paul

Thanks for this.

Does a 15620 have a power reserve of about 72 hours? I thought it would be less that that! Would I be correct in thinking that the power reserve increased with the 116520 version?

1,700 turns sounds like an awful lot bearing in mind that the large majority of arm / wrist movements will not generate a full turn of the rotor. Does that represent a full 'recharge' from stopped?

I think I'll try experiment next time I wear a Rolex. Just give it a couple of turns of the crown to start it in the morning and then just wear it. I would be interested to see if wearing it for about twelve hours or so charges it enough to keep running through the night. If it does keep working, wear it for a week and then see how long it would run for after taking it off.

Thanks again for your reply.

[padi56]

Originally Posted by ratty

Hi Paul

Thanks for this.

Does a 15620 have a power reserve of about 72 hours? I thought it would be less that that! Would I be correct in thinking that the power reserve increased with the 116520 version?

1,700 turns sounds like an awful lot bearing in mind that the large majority of arm / wrist movements will not generate a full turn of the rotor. Does that represent a full 'recharge' from stopped?

I think I'll try experiment next time I wear a Rolex. Just give it a couple of turns of the crown to start it in the morning and then just wear it. I would be interested to see if wearing it for about twelve hours or so charges it enough to keep running through the night. If it does keep working, wear it for a week and then see how long it would run for after taking it off.

Thanks again for your reply.

The 16520 will have the cal 4030 the modified Zenith movement power reserve around 48 hours.From 2000 on 116520 Rolex first ever in-house made chronograph movement was introduced with the cal 4130,power reserve on a full wind around 72 hours.And to fully manually wind would need around 50 full crown turns clockwise only.By just wearing depending on how active you are its doubtful if many will reach full mainspring power.But on the wrist when mainspring is at full power the mainspring just slips in the spring barrel, as you cannot overwind like say a manual wind watch..

[ratty]

Originally Posted by padi56

The 16520 will have the cal 4030 the modified Zenith movement power reserve around 48 hours.From 2000 on 116520 Rolex first ever in-house made chronograph movement was introduced with the cal 4130,power reserve on a full wind around 72 hours.And to fully manually wind would need around 50 full crown turns clockwise only.By just wearing depending on how active you are its doubtful if many will reach full mainspring power.But on the wrist when mainspring is at full power the mainspring just slips in the spring barrel, as you cannot overwind like say a manual wind watch..

Hello Peter

I hope you are OK.

Thanks for this.

I thought the 16520's reserve was about 50 hours.

As I said originally, I was quite surprised that the watch continued to run for about 32 hours after being taken off. This represents about 65% of it's potential 50 hours ish maximum power reserve. I took it off in the morning after getting up so it had already been stationary for about another 9 or 10 hours prior to this. 32 plus 9 = 41 hours which is about 82% of it's potential maximum. The day before, I had got up and then driven from the Lake District to Hertfordshire via the Scottish borders. So, after sleeping for a night, driven for a day and slept for another night the watch still had about 65% of it's power reserve intact! For a watch with a potential 50 hours ish maximum power reserve a decent nights sleep probably reduced the power reserve by about 18%. Two nights would take that to about 36% and lots of driving would not 'charge' it much at all. The figures add up reasonably well to suggest that the watch was still recharging to it's maximum power reserve during the day despite, as I said, not being particularly active during the day.

Considering the watch was fully wound then worn for 5 or 6 weeks without any more manual winding during that time, I don't think that's bad at all for a watch this old. It might also suggests that I have been more active than I thought!

Anyway, well done watch, and I look forward to wearing you for many more years!