Short answer

A replica IW371466 is worth buying only when the case measures 41 mm across, the subdials sit at 12 and 6, and the chronograph resets to zero in one push. Check the dial print under a loupe, the gap between the subdials, the pusher feel, and the movement type before you send money. A seller who cannot provide a macro photo of the dial and a running chronograph video is a pass.

Know the reference before you compare

The IW371466 sits in the IWC Portugieser Chronograph family: a 41 mm steel case, a slim stepped bezel, leaf hands, and two subdials. The counter at 12 tracks chronograph minutes, the counter at 6 runs small seconds. The genuine line has used two movement generations, a modified Valjoux 7750 base in the 3714 references and the in-house 69355 in the newer generation. Confirm which generation your target reference belongs to, because subdial spacing, case thickness, and rotor noise differ between them.

Step by step checks

1. Case and bezel

  1. Measure the case across the bezel without the crown. It should read 41.0 mm.
  2. Measure thickness. A copy that reads 15 mm has the wrong caseback or a spacer ring inside.
  3. Run a fingernail over the bezel edge. The genuine edge is polished and slightly domed, not a flat slab.
  4. Check lug width. It should be 20 mm, and the lugs should curve down toward the wrist.

2. Dial and printing

  1. Look at the brand text and the line above the subdial at 12. Letters must be crisp and evenly spaced, with no ink bleed.
  2. Check the subdial rings. Both should match in diameter and sit on the same horizontal axis.
  3. Inspect the applied numerals and hands for plating depth. Thin, washed out gold tone points to a low grade finish.
  4. Ask for a photo in daylight, not studio light. Dial texture and lacquer depth show up there.

3. Chronograph and winding

  1. Start the chronograph and compare the minutes counter at 12 against the central seconds.
  2. Reset. Both hands must snap back to zero together. A slow creep back means a worn reset hammer.
  3. Time the pusher travel. Start and stop should feel firm with a short throw; a mushy pusher is a common flaw.
  4. Wind the crown 30 turns and listen. A dry, grinding sound points to an unserviced 7750 base.

4. Movement

  1. Ask which movement the watch uses. The 7750 clone is standard; an in-house style clone costs more.
  2. Look through the caseback. Shallow or uneven rotor engraving is a tell.
  3. Check the beat rate with a timegrapher app. Expect 28,800 vph and a steady rate line.

5. Strap or bracelet

  1. Confirm the clasp is signed and the spring bars seat in the lug holes.
  2. Bend the strap. Stiff, plastic-feeling leather is the usual stock item and needs replacing.

Questions for the seller

  • Can you send a video of the chronograph starting, running, and resetting?
  • What is the measured case thickness in millimeters?
  • Which movement is inside, and has it been serviced?
  • What is the return window if the watch fails a timing check?

Red flags

  • Stock factory photos instead of photos of the actual watch.
  • Subdials at 3 and 9, which is the wrong layout for this reference.
  • Prices far below the market for the stated movement grade.
  • No answer on movement type or service history.