The ref 26470 is the 42 mm Royal Oak Offshore that Audemars Piguet brought back in 2014. A replica of this reference lives or dies on four measurements: case diameter, case thickness, subdial placement, and the beat rate of the movement inside. When those four line up, the watch reads correctly on the wrist. When one is off, no amount of dial finishing hides it.
Specs to measure against
The genuine 26470 measures 42 mm across the bezel and about 14.6 mm thick at the case middle. It runs the Calibre 3126/3840, an in-house 3120 base with a Dubois-Depraz chronograph module stacked on top. That movement beats at 21,600 vibrations per hour and carries roughly 50 hours of reserve. The dial uses the Mega Tapisserie pattern, with chronograph counters at 12, 6, and 9, a running seconds hand at 9, and a plain date aperture at 3. Water resistance is rated at 100 m. Steel versions carry a ceramic crown and pushers, which is one of the easiest details to check by hand.
Before you start
- The exact reference code you are inspecting, since dial colour, hand finish, and strap material change with it.
- Digital calipers.
- A 10x loupe.
- A timegrapher.
- A watchmaker willing to open the caseback for a movement check.
How to evaluate a replica 26470
- Confirm the reference code on the caseback before anything else. The dial colour, hand style, and strap material follow from that code, so a mismatch here means the rest of the inspection is pointless.
- Measure the case across the bezel with the crown excluded. The figure should land at 42.0 mm.
- Measure thickness at the thickest point of the case middle. Anything past 15 mm sits visibly taller than the genuine watch and pushes the watch off the wrist when worn.
- Check the strap width at the lugs and again at the clasp, then compare both figures with the published dimensions for your variant.
- Study the dial under the loupe. The Mega Tapisserie squares should have sharp, slightly raised tops with even spacing across the whole surface. Flat, blurred, or unevenly spaced squares are the most common dial fault.
- Trace the subdial layout. Counters belong at 12, 6, and 9, with the date window at 3 and no magnifier over it.
- Reset the chronograph and watch where the centre seconds hand lands. It should return to 12 and stop. A hand that settles a few degrees off, or drifts after reset, points to a weak module or a badly seated hand.
- Press each pusher. Screw-down collars should turn smoothly and the pusher travel should feel crisp rather than gritty or spongy.
- Look at the crown. Steel 26470 models use a ceramic crown and pushers, so a plastic or coated metal part is an immediate fail.
- Have the caseback opened and identify the movement. The genuine calibre is the 3126/3840. Most replicas use a modified Asian 7750, which runs at 28,800 vibrations per hour, or a decorated clone built to imitate the 3 Hz rhythm of the original. Put the watch on a timegrapher to settle it.
- Read the timegrapher results. Rate within about plus or minus 15 seconds per day, amplitude between 260 and 310 degrees, and beat error under 0.5 ms are reasonable targets for a well-built replica.
- Inspect the caseback engraving under the loupe. Lettering should be crisp and evenly cut, with a serial and reference format that matches the variant.
Red flags that end the inspection
- Case thickness well past 15 mm.
- Flat or poorly spaced Tapisserie squares.
- A date font that is too thick or sits low in the window.
- Chronograph hands that fail to zero cleanly.
- Shallow, soft caseback engraving.
- A crown or pusher set that does not match the variant material.
Wear and service notes
A chronograph module adds friction, so plan on a service interval shorter than you would accept on a simple three-hand watch. Keep the pushers screwed down when the chronograph is not in use, and treat any water resistance claim as unverified until a watchmaker has checked the gaskets and caseback seal. The rubber strap on most 26470 variants survives daily wear well, but the alligator option needs rotation to avoid cracking at the lug ends. If the watch arrives running fast or slow, have it regulated before judging anything else about the build quality.