difference IWC 5102-03 and IW5102-05, althrough the same caliber?

Hello, I need your help.

I recently acquired two watches.

IWC 5102-03

IWC 5102-05

Both have the same caliber (59215).

With the 5102-03, you don't feel any end resistance when winding it, as you normally would with a

manual-winding watch.

As with my Monopusher 5153-01 (also manual winding, 8-day power reserve), the effect is like that of an automatic watch.

This watch was even sent to IWC, who said that this was normal,

that the watch had a drag spring ?, if I remember correctly. My watchmaker didn't know the

details either, and there is no indication in the manual that the watch cannot be overwound.

The 5102-03 is identical to the monopusher, no overwinding possible, no end resistance.

As already mentioned, my 5102-05 has the same caliber etc. as the 5102-03,

but there is a massive end resistance.

Both watches are running correctly.

Perhaps someone knows more about this?

I can't find anything on the web; the information about the monopusher came after I sent the watch to IWC.

I would like to avoid sending watches to IWC on a whim, as they are working perfectly.

I just want to know if everything is as it should be.

I would be very grateful to you all for your information.

thank you very much!

ulrike

The difference between the IWC 5102-03 and IW5102-05, despite sharing caliber 59215, lies in the winding feel. The 5102-03 has a drag spring mechanism that prevents over winding, giving a smooth, automatic-like winding experience with no end resistance. The 5102-05 lacks this feature, so it has noticeable end resistance when fully wound. Both behaviors are normal for their respective models.

Thank you very much for the explanation, now I'm reassured -:)

The IW5102-03 and IW5102-05 use the same in-house caliber, so mechanically they are identical in movement, power reserve, and reliability; the differences lie mainly in external details such as dial finish, hand and font colors, and strap/buckle combinations as well as production context, with one reference sometimes made for a specific market or catalog period. Essentially, they are the same watch internally, with minor aesthetic and configuration differences justifying separate reference numbers.