Short answer
A replica Big Pilot sold as IW5105 is worth buying when the case measures 46.2 mm, the dial carries the correct oversized numerals and a power reserve hand at 3 o'clock that actually tracks the mainspring, and the movement hacks and winds without grit. Confirm those three points in writing and in QC photos before you send money. Everything else is cosmetic.
Before you order
- Decide which Big Pilot you want to match. The 46.2 mm reference and the 43.8 mm Big Pilot 43 are different watches with different dial proportions and lug spacing.
- Set a budget band: entry automatics, mid tier with decorated movements, and top tier with a working multi-day power reserve.
- Ask the seller for the factory name, movement code, and case diameter in millimeters.
- Request QC photos on a plain background plus a short video showing the seconds hand and the power reserve hand in motion.
What the IW5105 label means
No catalogued IWC Big Pilot carries the number IW5105. The string appears in seller listings that mirror the 46.2 mm Big Pilot, so treat it as a listing label and not a specification. Pull the real specs from the manufacturer page for the reference the seller claims to replicate, then compare line by line: diameter, thickness, lug width, crystal type, crown size, and water resistance. Gaps at this stage predict gaps on the watch.
Movement: the part that sets the price
Three tiers show up in the replica market. The cheapest runs a basic automatic under a decorative plate, and the power reserve hand never moves. The middle tier uses a modified automatic with a linked indicator that follows the mainspring. The top tier copies the architecture of the calibre 52110 far enough to run a multi-day reserve, and the tell is a reserve hand that reaches the end of the scale after a full wind and falls at a believable rate. Ask for a 48-hour timing video to see the hand travel.
Case, dial, and strap checks
The Big Pilot dial lives or dies on the numerals. Look for straight edges, even lume fill, and a minute track that runs without breaks. The conical crown should be large, grippy, and centered on the case band. On the original, a soft-iron inner case adds mass, so a replica that feels light in the hand is a hint about the case material. Strap width should match the lug gap to the half millimeter, and the buckle should carry the same finish as the case.
Step-by-step inspection on delivery
- Measure the case with calipers across the bezel at 9 and 3 o'clock. Accept nothing outside 46.0 to 46.4 mm on a 46 mm build.
- Inspect dial print under a loupe. Numerals and text need crisp edges, no bleeding, and no misalignment against the chapter ring.
- Wind the crown 40 turns and watch the power reserve hand. It should climb in small steps, not jump or stall.
- Set the time and confirm the hacking lever stops the seconds hand. Restart and compare the beat against a reference clock for 60 seconds.
- Work the crown through each position, then push it home and check that it seats flush with the case band.
- Examine the caseback engraving. Reference text and serial should sit level and cut deep enough to catch a fingernail.
- Flex the strap at the lugs. Leather should be supple with even stitching, and the tang should center in each hole.
- Run the watch on a timegrapher and record rate, amplitude, and beat error in six positions. Keep the printout for warranty claims.
Red flags
- Photos shot only from the front, or a video that never shows the caseback.
- A power reserve described as decorative while priced at the top tier.
- Diameter quoted as "about 46 mm" with no caliper photo.
- No timegrapher reading and no return window.
Living with a 46 mm pilot
This is a large watch. On a 6.5 inch wrist the lugs sit near the edge, so try a 22 mm strap before you commit to the size. Keep the crown clear when you set the watch down, have the movement serviced every three to four years, and get the gaskets checked before any contact with water.