Rolex · Datejust 31

Strap for Datejust 31 Rolesor Everose Domed Diamond / Jubilee / Chocolate Roman

Takes 16 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width16 mm
Case diameter31 mm
Reference178341-0009
FamilyDatejust 31
MovementRolex caliber 2235 hours, minutes, seconds | date | chronometer
CaseRose Gold, Stainless Steel

Spring bar

Spring bars for Rolex

The right category for this model · choose the 16 mm size

Straps for the Datejust 31 178341-0009

Selected for the 16 mm lug width

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The Datejust 31 178341-0009, seen from the bench

The Rolex Datejust 31 ref. 178341-0009 belongs to one of the most enduring watch lineages of the 20th century. This 31mm case combines Oystersteel and 18-karat Everose gold in a two-tone configuration, housing the Rolex caliber 2235 automatic movement with Paraflex balance and Parachrom hairspring. Water-resistant to 100 meters, the watch features a fluted Everose bezel and measures 31.00mm in diameter. The lug width is 16mm, specific to this 31mm variant and incompatible with 36mm or 41mm versions. Choosing the correct 16mm aftermarket strap requires precise measurement of the interior distance between lugs.

Frequently asked questions

What is the lug width of the Rolex Datejust 31 178341-0009?

The Rolex Datejust 31 reference 178341-0009 has a lug width of 16mm. This measurement is specific to the 31mm diameter variant and is taken as the internal distance between the two case lugs at the strap attachment point. Only straps with a 16mm fitting should be used to ensure a correct, play-free installation.

What is the best strap for the Rolex Datejust 31 178341-0009?

For the Datejust 31 178341-0009, with its two-tone steel and Everose case, the most appropriate materials are: polished alligator belly in bordeaux or midnight blue for formal settings, shell cordovan in cognac or dark brown for a more personal character with an evolving patina, and vegetable-tanned calfskin for daily wear. A brushed steel deployant clasp is the most coherent closure choice for this two-tone reference.

How do you change the strap on a Rolex Datejust 31?

To replace the strap on the Datejust 31 178341-0009, the spring bars connecting the strap to the case lugs must be removed. A fine-tipped springbar tool is inserted into the side hole of the lug and used to compress the bar. Care must be taken to avoid scratching the Everose gold case. Alternatively, Atelier Casati Milano can perform the replacement on-site by appointment.

Are there aftermarket straps compatible with the Rolex Datejust 31 178341-0009?

Yes. The aftermarket offers high-quality straps with a 16mm fitting compatible with the Datejust 31 178341-0009. Milano Straps produces handcrafted straps in alligator, shell cordovan and vegetable-tanned calfskin, fitted with standard 16mm spring bars. It is important to verify that the strap end profile — curved or straight — matches the lug geometry of the case for a precise fit.

How long does a leather strap last on a Rolex Datejust 31?

The lifespan of a leather strap on a Datejust 31 depends on the material and frequency of use. A quality alligator strap, rotated regularly and kept away from water and excessive perspiration, typically lasts 2–4 years. Shell cordovan, being denser and more compact, can exceed 5 years. Milano Straps products are covered by an 18-month warranty against manufacturing defects.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

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Casati Milano · Via XX Settembre 15, Milan · by appointment only