A fake Audemars Piguet ref 5402 is a copy of the first Royal Oak from 1972, and it gives itself away in four places: case thickness, dial texture, bezel screw shape, and the movement behind the caseback. The genuine 5402ST is a 39 mm steel watch with an integrated bracelet and the thin caliber 2121. Most copies match the outline and stop there, because a real thin automatic movement costs more than the whole fake.
What is the Audemars Piguet ref 5402?
The ref 5402ST is the original Royal Oak, launched in 1972 and designed by Gerald Genta. It was the first steel luxury sports watch with an integrated bracelet, and many buyers of the day struggled with the idea of a steel watch priced near gold models. Collectors now call it the Jumbo.
Core specs: 39 mm case, octagonal bezel held by eight visible hexagonal screws, a thin profile, a Tapisserie dial with a raised grid pattern, and a date at 3 o'clock. The movement is the caliber 2121, a thin automatic shared with other high-end brands of the era.
Production ran through the 1970s in batches labeled A, B, C and D, and versions in steel, two-tone and gold exist. Later Royal Oak references replaced it, which places the 5402 at the start of the line.
How do you spot a fake ref 5402?
Case size and thickness
Measure the watch and look at a side profile. A real 5402 is 39 mm across the bezel and thin enough to slide under a shirt cuff. Fakes often run 40 to 42 mm wide and 10 mm or more thick, because the movement inside needs the room.
A thick case paired with a 5402 dial is a red flag. The original case was built around a thin movement, so extra depth has to come from somewhere.
Dial and Tapisserie pattern
The original dial carries a stamped grid of small raised squares, known as petite Tapisserie. Fakes print the pattern or stamp it shallow, so the squares look flat under a loupe and the edges catch light in the wrong way.
Inspect the AP logo at 12 o'clock, the lettering weight of the brand name, and the date wheel font. Copies often use a generic date disc with the wrong typeface or a date window that sits off center.
Bezel screws
A real 5402 has eight hexagonal screws that pass through the bezel and clamp it to the case with nuts on the back side. Copies use screws that are decorative, and they tend to be larger, flatter, or standing above the bezel surface.
View the screw heads from the side. Genuine screws sit near flush with the bezel ring.
Movement
Ask for a movement photo before any money moves. The caliber 2121 is a thin automatic with a gold rotor, fine finishing and a date function. Most fakes run on quartz or a thick automatic, which is why the case is deeper than it should be.
Quartz is the loudest tell on a reference that never used it. A second hand that ticks once per second means the watch is not a 5402.
Caseback engravings
The back of a 5402 is engraved with the reference, a serial number and branding, cut into the metal with crisp lettering. Fakes use laser etching that looks too dark, too deep or too wide, and the font seldom matches period examples.
Serial numbers follow the production series. A number that does not fit the A, B, C or D pattern of the case style deserves a question.
Bracelet and clasp
Check the link taper from the case to the clasp, the end-link fit at the lugs, and the stamping on the clasp. Copies often show uneven gaps, soft polishing and a clasp stamp with the wrong depth.
Which mistakes show up on almost every fake 5402?
- Case too wide and too thick for a thin automatic movement.
- Printed or shallow dial pattern instead of stamped Tapisserie.
- Decorative bezel screws that do not bolt through the case.
- Quartz movement or a thick automatic with no gold rotor.
- Caseback text with the wrong font, spacing or serial format.
- Bracelet with soft edges and a loose fit at the lugs.
Why is the 5402 faked so often?
The 5402 is the first Royal Oak, so it carries the history of the whole line. Auction results for clean examples sit well above the price of a modern steel sports watch, which pulls in copies.
Small production also helps fakers. Fewer real watches exist than buyers want, so a copy can pass in a photo listing where nobody measures the case.
Which listing photos should raise questions?
- No side profile shot, or a profile that crops out the caseback.
- Dial photos taken at an angle that hides the grid texture.
- Bezel shots from straight above, where screw height is invisible.
- No movement photo on a watch sold as vintage.
- Blurry serial engraving with no close-up of the numbers.
How should you check a ref 5402 before you buy?
- Ask for case measurements and a side profile photo next to a ruler.
- Request a clear movement photo and the caliber number.
- Compare the dial pattern with known 5402 examples at high magnification.
- Read the caseback engraving and check the serial against the series.
- Inspect the bezel screws from the side, then count them. There should be eight.
- Have an independent watchmaker open the case before payment is sent.
Frequently asked questions
Was the ref 5402 ever made with a quartz movement?
No. Every 5402 left the factory with the caliber 2121 automatic. Any quartz 5402 is a fake or a later copy.
How many bezel screws does a real Royal Oak 5402 have?
Eight hexagonal screws on the bezel, with matching nuts inside the case. Count them and confirm that they hold the bezel down rather than sitting on the surface.
Is the 5402 the same watch as the Royal Oak Jumbo?
Yes. Jumbo is the collector nickname for the 39 mm ref 5402, which was the largest Royal Oak of its time.
Do fake 5402 watches use solid gold?
Most use gold plating or a gold-colored alloy over a steel case. A jeweler can settle the question with a magnet and a hallmark check, since real gold cases carry stamps.
What does a fake 5402 cost compared with a real one?
Copies sell for a few hundred dollars. Real 5402ST examples trade in the tens of thousands and higher, depending on series and condition. That gap is the reason copies exist.
What should you do if a 5402 turns out to be fake?
Stop the sale and ask the seller for the source in writing. If you already paid, collect photos, messages and payment records, then report the listing to the platform and dispute the charge with your bank or card issuer.
For buyers who choose modern tribute or replica pieces on purpose, the same checks still matter. A copy with a printed dial and a quartz movement is not the same product as a high-grade tribute running an automatic, and the price should reflect what is inside the case.