Audemars Piguet Royal Oak 4100SA Review

THE FIRST LOOK

Audemars Piguet Royal Oak 4100SA First Impressions

What hits you the moment you pick up the two tone 35mm Royal Oak.

The Audemars Piguet Royal Oak 4100SA lands in your palm heavier than a 35mm watch has any right to feel, and that is the first thing worth knowing about it. Gold does that. The bezel, the eight hexagonal studs, the hands, the applied markers and every center link of the bracelet are 18k yellow, and the mass sits exactly where your fingers close around the case. Of all the vintage pre-owned Audemars Piguet watches that cross our bench, the Audemars Piguet Royal Oak 4100SA is the one buyers underestimate from photographs and reassess within about four seconds of holding it.

The second impression is the color relationship. Audemars Piguet paired the gold with a slate grey petite tapisserie dial rather than the champagne or cream you would expect from a 1970s steel and gold watch, and that grey pulls the whole piece back from anything loud. It reads as a steel watch that someone has quietly outlined in gold. In daylight the brushed case top, the mirrored bevel and the warm 3N bezel each sit in their own tonal register without competing. Among two tone Audemars Piguet watches, this is the most restrained execution the brand has ever built, and it is exactly why the 4100SA lands on wrists that would never wear a full gold sports watch.

THE WEARING EXPERIENCE

How the Audemars Piguet Royal Oak 4100SA Wears on the Wrist

Real dimensions, real presence, and who this 35mm case actually fits.

The Audemars Piguet Royal Oak 4100SA measures 35mm across the octagon and roughly 44mm from lug tip to lug tip, but neither number tells you how it sits. The integrated bracelet is the deciding factor. The first link on each side barely articulates, so the effective footprint stretches closer to 50mm and the watch covers more wrist than a 35mm dress watch ever would. Practically, that means it works cleanly on wrists from about 6.0 to 7.25 inches. Above 7.25 inches it starts reading as deliberately small rather than correctly sized, which some collectors want and others do not.

Thickness is where this reference quietly beats almost everything modern. At roughly 7.2mm the 4100SA slides under a cuff with room to spare, and because the bracelet drops immediately from the case rather than sitting on a lug, there is no hinge point digging into the back of your wrist. All up it weighs around 100 grams, which is about 15 grams more than the steel version and enough to feel substantial without becoming a paperweight. Compared with a modern 41mm Audemars Piguet Royal Oak 15202 or 15500, this is a completely different wearing proposition: less presence, far more comfort, and a watch you genuinely forget about by mid morning.

SHOP THIS WATCH

Shop the Royal Oak

Browse authenticated Audemars Piguet Royal Oak watches available now at WatchGuys.

Vintage two tone Royal Oaks move quickly and rarely arrive two at a time. If the proportions and the slate grey dial sound like your watch, here is what we currently have in the case.

THE DETAILS

Audemars Piguet Royal Oak 4100SA Specifications

Case, dial, bezel and bracelet on the two tone 4100, component by component.

Case

The Audemars Piguet Royal Oak 4100SA case is a three part stainless steel construction topped with an 18k yellow gold bezel, and its architecture differs from the 5402 that came before it. Audemars Piguet merged the bezel and the central casing ring into a single component, which shortened the gasket run and allowed the diameter to come down to 35mm without distorting the octagon. Finishing is where the budget went. Case and lug tops are brushed in one direction, the bevels are mirror polished, and the line where they meet is hard rather than rolled. On an honest example you can read that line with a loupe. On an over polished one it goes vague, and that is the fastest way to judge a 4100SA from photographs alone.

Two practical notes. The crown does not screw down, so the 50 metre rating Audemars Piguet published in 1977 should be treated as historical rather than current. On a watch this old, with gaskets this old, assume splash resistance and keep it away from water. The crystal is flat sapphire and sits low enough in the bezel that it almost never takes an edge knock. The caseback is solid, screwed, and carries the case and reference numbers, which should be crisply cut. Shallow or soft engraving usually means the back has been polished.

Dial and Bezel

The dial on the Audemars Piguet Royal Oak 4100SA is a slate grey petite tapisserie made by Stern Freres, and it is what makes the whole two tone scheme work. The waffle is smaller and tighter than the grande tapisserie on modern Royal Oaks, so it holds light in tiny points rather than broad squares, and at arm's length it reads as textured charcoal rather than a pattern. Applied gold stick markers and matching gold hands carry the original tritium, which on every surviving example has aged to cream and no longer glows. Correct examples pair a colour matched grey date disc at three with the old style flat Audemars Piguet signature at twelve. Service dials read Swiss Made rather than Swiss, and they cost real money at resale.

The bezel is solid 18k yellow gold, polished on top with a fine brushed inner flank, and secured by the eight hexagonal studs that are really the visual signature of the entire design. Gold is softer than steel and shows its history differently: expect rounded stud corners and a slightly satin patina on the bezel face on any watch that was actually worn. That is normal wear, not damage. What matters more is whether the bezel edges are still sharp where they meet the case, because gold refinishing removes material that nobody can put back.

Bracelet

The Audemars Piguet Royal Oak 4100SA runs the reference 477 bracelet, a steel and gold integrated design with gold center links that taper hard from the case toward a hidden double folding clasp signed by Audemars Piguet. There is no micro adjustment and no half link system, so sizing is a matter of removing links and living with the result, which is worth planning around if your wrist swells in heat. The articulation is excellent for a bracelet designed in 1976, and because each link is genuinely small the bracelet conforms rather than draping.

Stretch is the single biggest pre-owned consideration on this reference. Four decades of daily wear works the link pins, and a stretched two tone bracelet is significantly more expensive to address than a steel one because the gold center links carry the wear. Hold the watch by the clasp and let it hang: visible gaps between links mean stretch, and a replacement bracelet from Audemars Piguet, when one can be sourced at all, can run into five figures. Budget for the bracelet before you budget for the watch.

EXPERT TIP | Robertino Altieri | WatchGuys CEO

What to Check on a Pre-Owned 4100SA

"Four things, in this order. One, hang the watch from the clasp and look for daylight between links, because bracelet stretch is what kills value on this reference. Two, check the gold bezel studs for rounded corners, which tells you how hard the watch lived. Three, look at the dial signature and the date disc colour, since a service dial takes real money off the price. Four, ask for the case and movement numbers and confirm the caliber is still a 2123 or a period correct 2124 or 2125, because a quartz conversion or a swapped movement changes what you are buying entirely."

UNDER THE HOOD

Audemars Piguet Royal Oak 4100SA Movement Review

How the Caliber 2123 performs where it matters: on the wrist, every day.

The Audemars Piguet Royal Oak 4100SA runs the Caliber 2123, a 26mm automatic built on a LeCoultre blank with 33 jewels, a 28,800 vph balance and roughly 38 hours of reserve. Audemars Piguet developed it because the 2120 used in the 5402 was too wide for a 35mm case, and shrinking the diameter by 2mm while adding only 0.2mm of height bought room for a center seconds hand, a first for the Royal Oak. That is the whole reason this watch sweeps and the Jumbo does not. Later production received the 2124 or 2125, a handful carry the quartz 2506, and plenty of survivors now run a 2225 fitted during service. Confirm which one you are buying.

In daily use the 2123 behaves like what it is: a thin, well made 1970s automatic. A properly serviced example holds a few seconds a day, respectable but not chronometer territory, and it needs wearing most days or the modest reserve runs out overnight. The rotor is quiet and the crown winds smoothly with no grit. There is no date pusher on the case, so correction runs through the crown and deserves a gentle hand at this age. The real ownership consideration is service. Parts for the 2123 are scarce, and the specialists who work on it are booked out. Buy a serviced watch with paperwork, or buy at a price that assumes you will pay for one.

EXPERT TIP | Robertino Altieri | WatchGuys CEO

Service Costs for the Caliber 2123

"Plan on roughly $1,200 to $2,000 with a vintage Audemars Piguet specialist, and expect a wait, because the people who do this caliber properly are not sitting around. If you send it to the brand, ask before they start whether they intend to replace the movement or refinish the case, and tell them in writing not to touch either. I have seen more value destroyed by a well meaning factory service on a 4100 than by forty years of honest wear. And always ask for the old parts back."

MARKET VALUE

Audemars Piguet Royal Oak 4100SA Price

What the two tone 4100 actually costs on the secondary market right now.

The Audemars Piguet Royal Oak 4100SA sits in a narrower band than most vintage Royal Oaks, roughly $16,000 to $27,000, with the volume of honest transactions landing between $19,000 and $23,000. The spread is driven almost entirely by three variables: bracelet condition, whether the case has been refinished, and whether the dial is original. A tired but original example with a stretched bracelet belongs at the bottom of that range. An unpolished watch with a crisp caseback, tight bracelet and factory dial belongs at the top, and there are far fewer of those than the listing count suggests.

Two tone remains the value entry point into the 4100 family, trading below the steel 4100ST despite being the more expensive watch when new and despite steel being the more common of the two at 2,721 versus 3,563 pieces. Full gold Audemars Piguet watches in the 4100BA configuration sit above both, propped up by bullion value. For context, buyers cross shopping this piece against a vintage two tone Rolex Datejust are looking at three to five times the money for the Royal Oak, which is the honest framing: you are paying for Genta design language and a hand assembled integrated bracelet, not for a more capable watch. Tiffany and Fred Paris co signed dials carry meaningful premiums and should be authenticated carefully.

HEAD TO HEAD

Audemars Piguet Royal Oak 4100SA Comparison

The two tone 4100 against the alternatives buyers actually cross shop.

Audemars Piguet Royal Oak 4100SA vs. Audemars Piguet Royal Oak 4100ST (Steel)

The Audemars Piguet Royal Oak 4100SA and the steel 4100ST are the same watch under the metal: same 35mm case architecture, same Caliber 2123, same petite tapisserie dial, same 477 bracelet. The choice comes down to how you want to be seen and what you want to spend. Steel is the purist's answer and the market prices it that way, trading at a premium despite being the more common of the two, because collectors buying Genta's original argument want the material that made it. Two tone is the better looking watch in person, warmer under artificial light, and cheaper. It also ages differently, since gold picks up satin wear that steel does not.

Robertino's Take

"Everybody asks for the steel 4100 and then puts the two tone on and goes quiet. That is the pattern, and it has been the pattern for years. The 4100SA is the better wearing watch and it is thousands cheaper, which almost never happens in this hobby. If you are buying it to flip, buy the steel. If you are buying it to wear, buy the two tone and stop overthinking it."

Audemars Piguet Royal Oak 4100SA vs. Patek Philippe Nautilus 3800/1A (Mid-Size Genta)

This is the comparison that actually decides wallets. The Audemars Piguet Royal Oak 4100SA and the mid-size Patek Philippe Nautilus 3800 are the same idea executed by two houses: shrink an oversized Genta sports watch, add a center seconds hand, keep the integrated bracelet. The Nautilus is the softer, more organic design with its rounded porthole case, and it carries the Patek Philippe premium that has only widened over the last decade. The Royal Oak is the harder, more architectural watch and now costs a fraction of the Patek. If the octagon speaks to you, the 4100SA delivers the more distinctive design for materially less money. If you want the name that compounds fastest at auction, that has been the Nautilus for fifteen years running.

THE BOTTOM LINE

Is the Audemars Piguet Royal Oak 4100SA Worth It?

The final word on the two tone 35mm Royal Oak.

Yes. The Audemars Piguet Royal Oak 4100SA is the most wearable vintage Royal Oak you can buy and one of the last genuinely underpriced entries into Genta's design, provided you buy a good one. It is perfect for the collector who wants an authentic 1970s Royal Oak, values comfort over presence, and has no interest in paying Jumbo money for a case they cannot wear all day. It suits smaller wrists without apology and it looks better in person than in any photograph ever taken of it.

Skip it if you need water resistance, if you want a watch you can hand to any service center without thinking, or if 35mm will nag at you every time you look down. Those are real objections that design pedigree does not fix. Skip it too if you are buying purely for appreciation, because steel and gold has consistently lagged full steel here. The strongest reason to buy is the one nobody puts in a listing: this is the only vintage Royal Oak that disappears on the wrist. Try one before committing by booking an appointment with an Audemars Piguet specialist, or start with a modern Audemars Piguet Royal Oak 15500 if practicality matters more than provenance.

Robertino's Take

"I have bought and sold enough 4100SAs to know exactly where the money goes: bracelet, dial, case. Get those three right and you own one of the great sleeper watches of the last fifty years. Get them wrong and you own a project. Buy the condition, not the reference, and never buy this one from photographs alone."

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