Does Pilot's Chrono IW377709 contain plastic bearings?

Apprentice 2 posts

5 Feb 2017, 8:13 p.m. 5 Feb 2017, 8:13 p.m.

Hi all,

A couple of weeks ago I bought my first IWC (and my first mechanical watch). I love it! I have been reading up a lot on the Valjoux 7750 movement and a lot of forums recommend that the chronometer is not left running in a 7750 because it has plastic bearings which are more prone to wear.

Not that I would ever run my chrono all the time - I would only use it occasionally anyway.

But I read on here somewhere that IWC source the best ETA 7750s and upgrade them further. Would these upgrades include ditching plastic for jewels by any chance? The thought of splashing out a four-figure sum on a prestigious watch only for it to contain plastic horrifies me slightly!

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Mr. Tonny Berteloot

Moderator 3566 posts

5 Feb 2017, 8:41 p.m. 5 Feb 2017, 8:41 p.m.

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There was a previous discussion on that matter here
and here
and with drawings here
No reason at all why a plastic part wouldn't be used as you can read.

Here is an answer by IWC found in the archives.

"We made experiences with other materials at the three parts. At least we
changed the brake only to another one made of metal. The reasons are
that the bearing for the centre wheel pinion is on a small spring. If a
ruby is used at this place it could be disturbed very easy and the
broken parts will be in the whole movement. We also do not change the
hour-wheel bearing at the calibre 7922 because there is not enough place
to set a ruby.

Kindest regards,

IWC Schaffhausen "

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Mr. Colin Pitman

Apprentice 2 posts

5 Feb 2017, 9:12 p.m. 5 Feb 2017, 9:12 p.m.

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Excellent stuff Tony - thanks. I did try the search function on the forum first but not much luck. The posts you linked to made for interesting reading. Glad to hear that plastic is used for its material properties and not for cost-cutting. As the author notes - the price difference would be negligible anyway.