If you plan to compare a fake IW3717 against a genuine IWC Portugieser Chronograph, compare the modified Valjoux 7750 version first. It is the only replica family that reproduces the real watch's dial architecture: one chronograph counter at 12, running seconds at 6, and a movement layout that matches what IWC used in the 3714 generation. Case finishing can be judged on any variant, but subdial spacing and hand function cannot be corrected after the fact, so the 7750-based build sets the ceiling for what the replica can be. Judge that one against the genuine, then use the rest of this guide to sort the weaker options.
Why the 7750 build is the only fair comparison
A comparison review is only useful if the two objects share a design. A quartz or decorated-automatic fake with three subdials is a different watch wearing a similar dial, and measuring it against a Portugieser Chronograph tells you nothing about how close a replica can get. The 7750-based version shares the genuine watch's mechanical logic: central chronograph seconds, a counter at 12, small seconds at 6, and pushers that start, stop and reset on a column and cam system rather than a glued-on module.
What to look for side by side
Case and proportions
Put calipers on both watches before you look at anything else. Diameter, thickness and lug width are the three numbers sellers most often blur, and they are the three numbers a photograph hides. The genuine case is thin for a chronograph, and a replica that gains a millimeter of height sits visibly higher on the wrist and changes how the lugs curve away from the strap.
Dial, hands and printing
Look at the subdial at 12 under a loupe. On the genuine it is a finished counter with crisp concentric texture and hands that sit at the correct height above the dial. On weaker replicas the texture is stamped shallow, the hands sit low, and the printed minute track thickens at the edges. Check the applied numerals for flatness and the leaf hands for a clean center crease.
Crystal, caseback and movement
Steel Portugieser Chronograph references use a sapphire display back, so the movement is part of the comparison, not a secret. A correct replica shows a 7750 base with the rotor and bridges finished to a plausible standard; a weaker one shows a rough casting under a decorative plate. Look at the crystal edge for a boxed profile and check that anti-reflective coating kills reflections rather than adding a blue cast.
Parameter bands to measure against
- Case diameter: 40.9 mm nominal, so accept 40.6 to 41.2 mm on a replica and treat anything outside that as a different case.
- Case thickness: roughly 12.3 to 12.6 mm on the genuine; most replicas land between 12.8 and 14.2 mm.
- Lug width: 20 mm, measured at the spring bar, not at the strap edge.
- Subdials: exactly two, one at 12 for elapsed time and one at 6 for running seconds. A third subdial means the maker used an unmodified movement or a quartz module.
- Beat rate: 28,800 vibrations per hour for a 7750 base, which reads as a smooth sweep rather than a ticking seconds hand.
- Power reserve: about 44 to 46 hours on a healthy 7750; anything far short points to a worn or cheaply assembled movement.
Options after the pick
- Modified 7750 with correct dial layout and a sapphire display back. This is the comparison standard and the only tier worth measuring against a genuine watch.
- 7750 with the right layout but a thick case, domed crystal or shallow dial texture. Useful only for studying dial printing, not for judging proportions.
- Quartz or faux-subdial builds. Skip these for comparison work; the pushers usually do nothing and the subdial hands are fixed.
Pitfalls
- Stock photographs. Sellers recycle images of the genuine watch or of a higher tier than the one shipped. Ask for dated photos of the actual unit on a plain background.
- Untested chronograph. Run the start, stop and reset cycle several times and confirm the counter at 12 advances and snaps back to zero.
- Thickness claims without calipers. A ruler against a screen proves nothing.
- Water resistance statements. A replica is not pressure tested, so treat any depth rating as marketing and keep it away from water.
- Legal and shipping risk. Importing counterfeit goods is illegal in the US and parcels can be seized, so budget for the possibility that the money is gone and the watch never arrives.
FAQ
Is a fake IW3717 the same size as the real one?
Usually close in diameter and often 0.5 to 1.5 mm thicker. Measure both with calipers rather than trusting a listing.
Can a replica use a real IWC movement?
No. The genuine calibre is not sold as a loose part, so any claim of an authentic movement inside a replica is false.
Why do some replicas show three subdials?
Because the maker used an unmodified 7750 with its standard 12-6-9 layout instead of reworking it to match the Portugieser dial.
How do I check the chronograph really works?
Start it, let it run for 60 seconds, confirm the counter at 12 has moved, then reset and verify the hand returns exactly to zero.