Caliber 69385 accuracy and use of chronograph function

Hello, everyone,

I bought about 3 weeks ago a brand new IWV Pilot Chronograph 43 mm from IWC USA. The accuracy is about +4.5 sec (never -) every day. I am not sure but I think it falls within the accuracy of the Caliber 69385. Can anyone confirm and tell me if I could obtain a better accuracy by having it serviced here in the US?

Additionally I read somewhere online that if I use the chrono function continuously, I would achieve a better accuracy. I tried for just a couple of days, and, amazingly, the accuracy was around +1-2 secs/day.

While I would be tempted to keep the chrono function on continuously, I also read that can wear the mechanism faster, even though there is a stronger evidence on non column wheel watches and this is a wheel watch, hence it could/should have less wear by running the chrono all the time.

I am a bit confused and unsure of what to do. Can anyone at IWC reply on these two issues?

Thanks!

Hi Pietrof

Congraulations on your new Pilot 43 Chronograph.

The two issues you mention are not issues at all.
+4.5 seconds per day is an excellent result, in fact better then the result while running chronograph which results in a +1 / -1 sec per day!

Simply run the chronograph when you need to time something, and you wouldn't even notice the rate change if you didn't use a timographer to measure the rate of the watch.

Mark, thanks for your reply but forgive my question: why do you say that +4.5 secs/day is better that the +1/-1 with the chronograph function on? Even if I have knowledge into watches since 20-30 year as a user of several good brands of watches, I would try and get a balanced +/- accuracy to make sure that eventually the loss of accuracy would balance itself with time.
is there something I am not considering?

and what about running the chrono all the time? Does it really wear the mechanism faster that just using it every once in a while?

Hi, nice choice!

I am not sure about your specific watch but I believe the specs for most IWC watches is that they should run between 0 and + 7 seconds a day.

It is better that the watch is slightly fast, then you can correct it by just pulling out the crown for the few seconds you need to get it on a perfect track again. If it is slow the correction will be more complicated.

To make a mechanical watch that keeps so good time is really a marvellous feat of mechanical engineering. One day is 86.400 seconds, 4 seconds in a day is about one part in 25.000. Can you imagine anything more precise except (shudder) a quartz watch. If you take a measuring tape and measure out 25 meters with the same precision, you would need to be able to measure the distance to within 46 micrometers (0.0046 mm). Is that even possible?

Great watch, enjoy!

Henrik

It is currently within specs, so no need to have it adjusted in an attempt to make it even more accurate. It may very well turn out with a less favorable rate. I am not sure how careful you are, but even a slight knoock against a door frame can affect the rate of a mechanical watch. I have not had a mechanical watch from any manufacturer maintain the same rate over an extended period of time with regular use.

I say just enjoy your watch while it is running with specs;)

I echo and agree with Ben's comment above. You may find that with wear that your IWC will settle in a bit at a different rate. What you have now is certainly acceptable and good. Enjoy your Pilot Chono and wear it in good health.

COSC specifications are +6,-4 secs/day. Your watch is fine. There's a lot of good information available about watch accuracy that's readily available.

Accuracy of a healthy watch is really a function of canceling out positional errors and two identically adjusted watches can deviate between individuals and their wearing habits.

Experiment by leaving your watch in different positions while off your wrist and noting the differences.

Enjoy!

Guys,

first of all thanks for your precious comments but my initial post was a two question one. The first was the concern on the 4.5 seconds that seems to be adding to my chronograph IWC every day. The next question was whether turning on the chronograph function on continuously does improve "dramatically" accuracy to a +1 sec a day.

what can you master comment on it especially regarding the potential wear of having the chrono function on a continuous basis.

I cannot comment on the amount of wear that running the chronograph all the time will inflict on the watch components, as I'm not a watchmaker. But the fact that all the additional wheels and pinions are running, must add some strain and wear to the movement.

Your second question is not a simple one to answer, as there is a difference between ACCURACY and RATE. As previous respondents have commented, your watch is within specified limits. The drop from +4s to +1/-1 may appear to be a perceived improvement, but in reality, it is not. The watch rate is dynamic, and may vary in different positions.

Please read the following article which may shed some light .....

www.hodinkee.com/articles/accuracy-what-is-it-and-does-anyone-actually-care#:~:text=The%20difference%20between%20accuracy%20and,you%20have%20an%20accurate%20watch.