The buying decision on a fake IW371717 comes down to four things: case profile, dial execution, the day and date window, and the movement inside. Get those right and the watch reads correctly at arm's length and holds up under a loupe. Get them wrong and no strap upgrade or confident listing copy will fix it. Before money changes hands, ask for four things: a flat, straight-on dial photo, a true profile shot of the case flank, a macro of the day-date aperture, and a short video with the chronograph started, stopped, and reset. A seller who cannot produce those four items is not a seller worth dealing with, whatever the description claims.
What the IW371717 actually is
The reference belongs to IWC's Pilot's Watch Chronograph family, the 3717 line that ran from the mid-2000s into the 2010s. The formula is consistent across the family: a brushed steel case in the 42 mm class, a matte black dial with white luminous Arabic numerals and broad sword hands, a day and date window at 3 o'clock, and a two-register chronograph layout with elapsed minutes at 12 and running seconds at 6. Inside the genuine watch sits Calibre 79320, a reworked Valjoux 7750 with a module for the day-date. That architecture explains most of what you are inspecting on a replica: the subdial positions, the pusher spacing, the crown size, and the stacked height of the case.
What to look for, part by part
Case profile and thickness
A chronograph built on a 7750 derivative is a tall watch, and replicas often make it taller than it should be. Look at the profile photo and check that the mid-case has a defined flank rather than a slab. The bezel should sit flush against the crystal without a visible gap, and the lugs should curve down toward the wrist rather than projecting straight out. Polished and brushed surfaces should meet at a crisp line, not a soft blur.
Dial and hands
The dial is where most replicas give themselves away. Numerals should be applied or printed with sharp edges and no ink bleed. The minute track should be continuous and evenly spaced. Subdial rings should sit at the same depth on both registers, and neither should look punched out of the main plate. Hand length matters: the minute hand should reach the inner track, and the chronograph seconds hand should reach the chapter ring at 12 without overshooting. Check lume color under daylight, since a greenish tint against a black dial is an instant tell.
The day-date window
This is the highest-value check on the whole watch. The aperture should be rectangular with square corners, the print should be crisp and horizontally aligned, and both discs should sit on the same plane. Ask for a photo with the day and the date at different positions, or a video of a date change. A disc that drags, sits crooked, or shows a different font weight from the rest of the dial is a fail, not a small flaw.
Crystal and coating
An anti-reflective coating on the inside only is correct for the family. Coatings on the outside scratch and haze, and a strong blue or purple flash on the dial is a sign of a cheap treatment. The crystal should be flat with a slight dome and should not distort the dial at a shallow angle.
Movement and chronograph feel
Ask which movement is fitted: an Asian 7750 clone, a Swiss 7750, or a decorated variant. All three can work, but the tier should be stated and reflected in the case thickness. On the video, the start should be instantaneous, the stop should be clean, and the reset should snap back to zero on both hands at once. Pushers should have firm travel with a positive click. A mushy pusher or a chrono hand that stops a hair off zero is a sign of a rushed build.
Caseback, engraving, and strap
Engraving should be deep and legible with even letter spacing, not laser-etched and shallow. On leather, the strap is often the cheapest part of the package, so factor in a replacement. Stitching should be tight and the lining should not feel like cardboard.
Parameter bands worth measuring
- Case width: measure across the bezel with calipers and expect it within about 0.4 mm of the stated reference figure.
- Thickness: within about 0.8 mm of the reference. Beyond that the watch sits high and the caseback leaves the wrist.
- Lug width: confirm against the reference before ordering straps, since a mismatch is expensive to correct.
- Subdial spacing: the two registers should be symmetrical around the center line, with equal gaps to the minute track.
- Date change: should occur cleanly, with the day and date flipping together rather than one lagging.
- Rotor noise: quiet when shaken. Grinding or rattle is a reject.
- Water resistance: treat any claim above 50 m as unproven unless the seller offers a pressure test.
The three tiers, described honestly
Entry tier: an Asian 7750 clone in a case that runs thick, printed dial markings that look fine in photos and flat in person, and a date wheel with a generic font. Acceptable as a beater, not as a stand-in for the real thing.
Mid tier: the sensible buy for most people. Correct case proportions, applied numerals, a properly aligned day-date, sapphire with inner coating, and a serviced 7750 derivative. This is where the fake IW371717 stops looking like a replica and starts looking like a watch.
Top tier: a Swiss 7750 or a well-finished clone with a decorated rotor, matched hands and lume, and a case that measures within spec. You pay for the last five percent, and only you can decide if that matters.
Common pitfalls
- Listings using genuine press photos. Reverse-image search the shots before you commit.
- Sellers who quote a movement name but cannot show the rotor through the caseback.
- Photos taken only at an angle, which hide dial printing and thickness.
- Describing a watch as 1:1 without listing what was actually matched.
- Pressure to pay outside a tracked channel, which removes any recourse.
- Strap and buckle treated as an afterthought in the photos, which usually signals the rest of the build.
FAQ
Is a fake IW371717 worth buying at all?
If you want the pilot chronograph look without genuine pricing, yes, provided you buy at the mid tier and check the four items listed above. The reference is a tool watch, so function matters more than finish.
Should I choose an Asian or Swiss movement?
Swiss 7750 derivatives hold tolerance better and are easier to service. Asian clones are fine when they have been regulated and the case is not built too thick around them.
How can I tell the thickness is wrong from photos?
Ask for a side shot with a coin or ruler next to the case, plus a wrist shot from the side. The gap between the caseback and the wrist is the giveaway.
What is the first thing to inspect on arrival?
The day-date change and the chronograph reset. Both take under a minute to test and both are expensive to correct later.
Can I wear it swimming?
Do not, unless the watch has been pressure tested. Gaskets on replicas are the first thing to fail and the last thing sellers mention.