Short answer
A 5402 replica copies the Audemars Piguet Royal Oak ref. 5402ST, the steel sports watch Gérald Genta designed in 1972. The original case measures 39 mm across and about 7.9 mm thick. Most replicas measure 9.5 mm to 10.5 mm thick. Case thickness is the first thing to check. The dial is the second: the 5402 carries the AP logo and the word Automatic, and nothing else above the date.
Audemars Piguet Ref 5402 Copy Guide: Judging a Royal Oak Jumbo Replica
The original in numbers
- Reference 5402ST, launched 1972, steel case.
- Case: 39 mm diameter, about 7.9 mm thick.
- Movement: caliber 2121, automatic, 3.05 mm thick, 19,800 vph.
- No seconds hand.
- Date at 3 o'clock.
- Bezel: octagonal shape, eight hex screws.
- Case: monobloc, no rear opening.
Caliber 2121 uses a Jaeger-LeCoultre base, the 920. Patek Philippe and Vacheron Constantin used the same base. AP kept the thinnest version at 3.05 mm.
Fake Audemars Piguet 5402: A Check Guide
Case thickness and caseback
The 5402 is a monobloc case. There is no separate caseback. A watchmaker removes the eight bezel screws, lifts the bezel and crystal, and takes the movement out through the front. A replica with a screw-down caseback on the rear is a different case design, not a copy of the 5402.
Measure thickness with calipers before you pay. A 10 mm case sits higher on the wrist than a 7.9 mm case, and the bracelet end links show the gap.
Top Pick: Replica Audemars Piguet Ref 5402
Dial
The dial has a stamped grid pattern, the Tapisserie. On the 5402 the squares are small and the grooves are fine. Print reads AP at 12 and Automatic above 6. Early dials do not read Royal Oak. The date window sits at 3, with a white disc on steel models.
Replica dials show thicker print, a coarser grid, and a date font with a short top serif on the 1. Look at the logo letters under a loupe. On the original the A and P touch at the base.
Bracelet
The bracelet is integrated into the case, with no separate end links. Links taper toward the clasp. Each link edge has a chamfer on both sides. Check the play between links, the clasp stamp, and the fit at the case. Loose links and sharp edges are common on copies.
Movement
No maker sells a 3.05 mm automatic at replica prices. Most 5402 replicas use a Miyota 9015 at 3.9 mm or a clone of the ETA 2824 at 4.6 mm. Both are thicker than the 2121. That extra height goes into the case, and the case grows past 9 mm.
The 9015 runs at 28,800 vph. The 2121 runs at 19,800 vph. A replica that adds a center seconds hand is wrong for this reference, because the 5402 has no seconds hand at all.
What to check before buying
- Case thickness. Under 8.5 mm is closer to the original. Over 10 mm is not.
- Seconds hand. The 5402 has none.
- Caseback. Monobloc on the original, with no rear opening.
- Dial text. AP and Automatic only.
- Bezel screws. Eight screws, slots lined up in one direction.
- Date font and window position.
- Bracelet taper and link chamfers.
Price
Replica 5402 watches sell for about $200 to $600. Original 5402ST examples sell at auction from about $60,000, with early A-series pieces and full sets higher. Price does not tell you which watch you hold. Measure the case, count the hands, and check the caseback. In the US, selling a copy as an original is fraud.