For more than a decade, collectors who loved the Audemars Piguet Royal Oak Chronograph (41mm) were forced to accept a major compromise: older replicas used modular Asian 7750 movements that made the watch 14.5mm thick with non-functional or swapped sub-dials. All of that changed when APS Factory (APSF) released the Royal Oak Chronograph Ref. 26240ST & 26240CE powered by the 1:1 integrated Calibre 4401 (SH4401) Flyback Chronograph.
- True Flyback Chronograph (Calibre 4401): While the chronograph is running, pressing the bottom pusher at 4 o’clock instantly resets the central seconds hand to zero and restarts a new timing sequence without pressing stop first!
- Exact 12.4mm Case Thickness: Because the SH4401 is an integrated column-wheel movement rather than a stacked 7750 module, APSF matches the genuine 41mm × 12.4mm Royal Oak 26240 profile to within 0.05mm.
- 50th Anniversary Skeleton Rotor & Exposed Column Wheel: Through the sapphire exhibition back, you can watch the vertical clutch and polished column wheel actuate in real time.
- Grande Tapisserie Dial Mastery: Crisp CNC-guilloché squares in Bleu Nuit, Khaki Green, Black, or Silver with snailed chronograph registers.
1. Inside the Integrated Calibre 4401 Flyback Architecture
When Audemars Piguet retired the Frederic Piguet 1185-based Ref. 26331 to launch the 50th Anniversary Ref. 26240, it introduced its in-house integrated flyback Calibre 4401—which swapped the positions of the 30-minute and 12-hour sub-dials, added an exhibition sapphire caseback, and introduced instant-jump date and flyback functionality.
On our Audemars Piguet Royal Oak Chronograph 26240 41mm Blue Dial SH4401, AP Royal Oak Chronograph 26240 41mm Black Checkered Dial, and AP Royal Oak Chronograph 26240 41mm Khaki Green SH4401, the chronograph pushers engage with a crisp, silky column-wheel click. Even better, APSF offers upgraded free-sprung balance wheel editions such as our AP Royal Oak Chronograph 26240 Ceramic Free-Sprung SH4401.
| 26240 Chronograph Metric | Genuine AP 26240ST | APS Factory (APSF SH4401) | Old 7750-Based Replicas |
|---|---|---|---|
| Movement Type | AP Calibre 4401 (28,800 vph) | Integrated SH4401 Column Wheel | Modified Asian 7750 |
| Flyback Reset Function | Instant Single-Press Flyback | True Working Flyback Reset | Standard Stop-Reset Only |
| Case Thickness | 12.40 mm | 12.40 mm (Exact 1:1) | 14.60 mm (+2.2mm Thick) |
| Sub-Dial Layout | 3: Hours / 6: Sec / 9: Mins | Exact Genuine 26240 Layout | Frozen or Swapped Registers |
| Bracelet Articulation | Hand-Brushed / Bevelled Links | APSF Tapered 904L / Ceramic | Stiff Unchamfered Links |
2. Steel (26240ST) vs Full Black/Blue Ceramic (26240CE)
Every Royal Oak bracelet contains 138 individually brushed surfaces and diamond-polished chamfers. APSF hand-finishes the transitions from the octagonal bezel screws (which are recessed hexagonal white-gold-toned bolts locked from the caseback) down through the tapering integrated links. For collectors seeking high-tech scratch resistance, our AP Royal Oak Chronograph 26240 Full Ceramic Silver Dial crafts both the octagonal case and the integrated bracelet from sintered zirconium oxide ceramic.
- ⌚ AP Royal Oak Chronograph 26240 41mm Bleu Nuit — Integrated SH4401 Flyback & Grande Tapisserie Dial
- ⌚ AP Royal Oak Chronograph 26240 41mm Black Dial — 12.4mm Slim Case & Exposed Column Wheel
- ⌚ AP Royal Oak Chronograph 26240 41mm Khaki Green — 50th Anniversary Rotor & Flyback Reset
- ⌚ AP Royal Oak Chronograph 26240CE Full Ceramic — Scratch-Proof Ceramic Case & Bracelet
- ⌚ AP Royal Oak Chronograph 26240 Free-Sprung Edition — Upgraded Free-Sprung Balance Wheel Architecture
Collector FAQ & Pre-Shipment QC Answers
Can I use the flyback button while the chronograph seconds hand is sweeping?
Yes! The SH4401 movement inside our APSF 26240 models is a true mechanical flyback chronograph—pressing the 4 o’clock pusher while timing immediately snaps the hands back to zero and begins a new lap.
How does the 26240 wear compared to the three-hand 15500ST?
Both share the exact same 41mm case width and integrated bracelet footprint; the 26240 is 12.4mm thick compared to 10.5mm on the 15500ST, giving it a slightly more substantial sporty presence.
