SOLD
Ref. 178240
31mm steel case
Black dial with Roman markers
2014
9.5 out of 10
Complete standard retail package in Rolex triple boxes
The Rolex Datejust 31 Black Roman Dial Ref. 178240 is a refined stainless-steel luxury watch that combines the Datejust’s classic design with a versatile midsize case. Its 31mm Oyster case, polished smooth bezel, black dial, Roman numeral hour markers, automatic movement, and date display create an elegant configuration suitable for daily wear and formal occasions.
Reference 178240 belongs to the previous generation of the Datejust 31 and has since been succeeded by the current reference 278240. The discontinued model remains attractive to buyers who prefer its established proportions, Rolex Calibre 2235 movement, and understated all-steel construction. Reference databases consistently identify the 178240 as a 31mm stainless-steel Datejust powered by Calibre 2235.
Key Specifications
Specification | Details |
|---|---|
Brand | Rolex |
Collection | Oyster Perpetual Datejust |
Reference | 178240 |
Case Size | 31mm |
Case Material | Stainless steel |
Bezel | Smooth polished stainless steel |
Dial | Black |
Hour Markers | Applied Roman numerals |
Crystal | Scratch-resistant sapphire |
Date Display | At 3 o’clock |
Date Magnification | Cyclops lens |
Movement | Rolex Calibre 2235 |
Movement Type | Automatic, mechanical and self-winding |
Power Reserve | Approximately 48 hours |
Water Resistance | 100 metres or 330 feet |
Bracelet | Oyster or Jubilee, depending on configuration |
Clasp | Folding Rolex clasp, configuration dependent |
Functions | Hours, minutes, seconds and date |
Production Status | Discontinued |
The case size, steel construction, sapphire crystal, date function, 100-metre water-resistance rating, and Calibre 2235 movement are consistently associated with reference 178240.
Classic 31mm Datejust Proportions
The 31mm case occupies a versatile position between Rolex’s smaller Lady-Datejust models and the larger Datejust 36 and Datejust 41.
Its size is suitable for:
Buyers who prefer traditional watch proportions
Women seeking more wrist presence than a 26mm or 28mm model
Men with smaller wrists
Collectors who prefer understated watches
Buyers looking for a dress watch that can still be worn daily
Actual wrist presence depends on wrist circumference, bracelet type, dial color, and personal preference. The black dial can make the watch appear visually compact and refined, while the polished bezel adds enough brightness to keep the configuration from looking overly restrained.
Black Dial with Roman Numeral Markers
The black dial gives this Datejust 31 a strong contrast and a more formal character than lighter silver, white, or champagne dials.
Applied Roman numeral markers provide a classical appearance while preserving the familiar Datejust layout. The dial includes:
Rolex crown at 12 o’clock
Applied Roman numeral hour markers
Central hour and minute hands
Sweeping central seconds hand
Date aperture at 3 o’clock
Cyclops magnification lens over the date
Minute track around the outer portion of the dial
Rolex produced several black-dial variations across the 178240 generation. Buyers should inspect the exact dial carefully because Roman, baton, diamond-set, and other configurations can carry different market values.
Smooth Stainless-Steel Bezel
Reference 178240 uses a smooth polished steel bezel rather than the fluted precious-metal bezel found on references such as the 178274.
The smooth bezel gives the watch a cleaner and more understated appearance. It also keeps the entire exterior in stainless steel, making the model more discreet than two-tone or white-gold-bezel Datejust configurations.
The polished surface reflects light and provides visual contrast against the brushed and polished sections of the case and bracelet.
Stainless-Steel Oyster Case
The 31mm Oyster case is designed to protect the movement against moisture, dust, and daily exposure. It incorporates:
Screw-down case back
Screw-down winding crown
Sapphire crystal
Twinlock-style waterproof crown system
Solid case construction
Water resistance rated to 100 metres
Rolex continues to rate comparable steel Datejust 31 models to 100 metres, while reference records for the 178240 report the same 10 ATM rating.
A pre-owned watch should not be assumed to remain water resistant merely because of its original specification. Gaskets age, crowns wear, and prior servicing can affect sealing. A current pressure test is recommended before exposing the watch to water.
Rolex Calibre 2235 Automatic Movement
The Datejust 31 Ref. 178240 is powered by the Rolex Calibre 2235, a mechanical automatic movement widely used in earlier midsize and ladies’ Rolex models.
Its principal characteristics include:
Automatic bidirectional winding
Central hours, minutes, and seconds
Instantaneous date display
Quick-set date adjustment
Stop-seconds functionality
Approximately 48-hour power reserve
High-frequency operation at 28,800 vibrations per hour
Reference listings for the 178240 consistently identify Calibre 2235 as its movement.
The Calibre 2235 predates the Calibre 2236 used in the current-generation Datejust 31. Although the newer movement offers updated technology and a longer stated power reserve, the 2235 remains an established Rolex movement with broad familiarity among qualified watchmakers.
Date Display with Cyclops Lens
The date window is positioned at 3 o’clock and changes rapidly around midnight. The Cyclops lens over the sapphire crystal magnifies the date for improved readability.
During inspection, verify that:
The date is centered correctly in the aperture
The numerals appear properly aligned
The date changes cleanly
Quick-set adjustment works smoothly
The Cyclops lens is correctly positioned
The font matches known Rolex date-wheel characteristics
Misalignment, unusual fonts, or poor magnification can indicate replaced components, incorrect parts, or authenticity concerns.
Oyster or Jubilee Bracelet
The Datejust 31 Ref. 178240 was available with different bracelet configurations. Depending on the original factory setup, the watch may have:
Oyster Bracelet
The three-piece Oyster bracelet has a sportier and more contemporary appearance. Its broader center links give the watch a solid and streamlined look.
Jubilee Bracelet
The five-piece Jubilee bracelet has a dressier appearance and is closely associated with the Datejust collection. Its smaller links provide additional articulation and visual detail.
The actual bracelet should be identified from the watch rather than assumed from the reference number alone. Examples of the 178240 appear on both bracelet styles in the secondary market.
For an accurate sales listing, state the installed bracelet explicitly and photograph the bracelet, clasp, end links, and reference markings.
Versatile All-Steel Construction
The all-steel design makes the 178240 easier to pair with different clothing and jewelry than many two-tone Datejust configurations.
It can complement:
Business clothing
Formal dresses
Casual outfits
White-gold or platinum jewelry
Silver jewelry
Other stainless-steel accessories
The black dial adds contrast while the smooth bezel prevents the design from appearing overly ornate.
Who Should Buy the Rolex Datejust 31 Ref. 178240?
This watch is suitable for:
Buyers seeking a midsize Rolex
Women who prefer a larger alternative to the Lady-Datejust
Men who favor traditional or compact watch sizes
Collectors looking for a discontinued Datejust reference
Buyers who prefer stainless steel over two-tone construction
Wearers who appreciate Roman numeral dials
Professionals seeking a discreet everyday luxury watch
Buyers wanting a watch that can transition from casual to formal use
Important Checks When Buying Pre-Owned
Before purchasing a used Rolex Datejust 31 Ref. 178240, verify:
Reference and serial numbers
Case size and bezel configuration
Dial originality and condition
Correct Roman numeral layout
Hand and hour-marker condition
Date-wheel alignment
Cyclops positioning and magnification
Sapphire crystal condition
Crown threading and winding action
Movement accuracy and amplitude
Date-change operation
Bracelet reference and end-link fit
Bracelet stretch and link count
Clasp function and markings
Case condition and signs of heavy polishing
Lug shape and symmetry
Water-resistance test results
Service history
Box and warranty-card consistency
Whether replacement or aftermarket parts are present
A professional authentication and movement inspection are strongly recommended before purchase, particularly when the watch is being sold without complete documentation.
Originality and Replacement Parts
The value of a pre-owned Rolex depends on more than external condition. Originality can materially affect desirability and resale value.
Check whether the following remain original or Rolex service replacements:
Dial
Hands
Bezel
Crystal
Crown
Bracelet
Clasp
Date wheel
Movement components
A genuine Rolex service dial or replacement bracelet is not necessarily undesirable, but it should be disclosed accurately. Aftermarket dials, diamond settings, bezels, and bracelet components can reduce collector appeal and may complicate future Rolex servicing.
Frequently Asked Questions
What size is the Rolex Datejust Ref. 178240?
It has a 31mm case diameter.
Is the Rolex 178240 made entirely of stainless steel?
Yes. Reference 178240 uses a stainless-steel case and smooth stainless-steel bezel. Bracelet material is also normally stainless steel.
Does the 178240 have a fluted bezel?
No. Reference 178240 is associated with a smooth polished steel bezel. Similar-looking references ending in different numbers may have fluted gold bezels or gem-set bezels.
What movement does the Rolex 178240 use?
It uses the automatic Rolex Calibre 2235.
How long is its power reserve?
Calibre 2235 provides an approximate power reserve of around 48 hours.
Is the Rolex 178240 waterproof?
It was originally rated water resistant to 100 metres or 330 feet. A pre-owned watch should undergo pressure testing before water exposure because seals and other components can deteriorate.
Is the black Roman dial original to this reference?
Black dials and Roman numeral configurations were offered within the Datejust 31 generation, but the specific dial on an individual watch must still be authenticated. Reference 178240 was sold with multiple dial styles and colors.
Does reference 178240 come with an Oyster or Jubilee bracelet?
It may be found with either bracelet depending on the original configuration. The installed bracelet and its originality should be confirmed from the actual watch.
Is the Rolex 178240 discontinued?
Yes. It belongs to the previous Datejust 31 generation and was replaced by the current reference 278240.
What is the difference between 178240 and 278240?
Both are stainless-steel Datejust 31 models with smooth bezels. The newer 278240 uses the updated Rolex Calibre 2236 and belongs to the current generation. Rolex identifies the current 278240 as a 31mm Oystersteel Datejust powered by Calibre 2236.
Is the 31mm Datejust only for women?
Rolex has traditionally marketed this size within its women’s range, but watch sizing is a personal preference. The 31mm case can also suit men with smaller wrists or collectors who favor traditional proportions.
Why Buy the Rolex Datejust 31 Black Roman Dial Ref. 178240?
The Rolex Datejust 31 Ref. 178240 offers a balanced combination of elegance, durability, and everyday versatility. Its black Roman numeral dial gives the watch a formal and distinctive appearance, while the smooth steel bezel and all-steel construction keep the design understated.
Its discontinued status, established Calibre 2235 movement, practical date display, sapphire crystal, and versatile 31mm proportions make it appealing to both first-time Rolex buyers and experienced collectors seeking a classic midsize Datejust.
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*Product pictures are actual unedited photos taken from our in-house studio.