Rolex · Datejust 31

Strap for Datejust 31 Stainless Steel Domed / Jubilee / Black Arabic

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
Reference178240-0019
FamilyDatejust 31
MovementRolex caliber 2235 hours, minutes, seconds | date | chronometer
CaseStainless Steel

Spring bar

Spring bars for Rolex

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

Straps for the Datejust 31 178240-0019

Selected for the 16 mm lug width

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The Datejust 31 178240-0019, seen from the bench

The Rolex Datejust 31 ref. 178240-0019 features a 31mm Oystersteel case with the caliber 2235 automatic movement, offering approximately 48 hours of power reserve and COSC chronometer certification with ±2/+2 seconds per day tolerance. The smooth case design, paired with a clean black Arabic dial and Cyclops magnification at 3 o'clock, delivers formal elegance and a refined mid-size profile. Lug width: 16 mm, a dimension requiring specific strap compatibility for proper fit and secure attachment.

Frequently asked questions

What is the lug width of the Rolex Datejust 31 ref. 178240-0019?

The Rolex Datejust 31 ref. 178240-0019 has a lug width of 16mm. This is a non-standard size compared to the more common 18mm or 20mm formats. It is essential to verify this measurement before purchasing an aftermarket strap to ensure a correct and secure fit between the case lugs.

What is the best strap for the Rolex Datejust 31 178240-0019?

For the Datejust 31 178240-0019, a polished-grain alligator strap enhances the formal character of the Oystersteel case. For daily wear, a vegetable-tanned calf leather strap develops a personal patina over time. Shell cordovan offers excellent dimensional stability. In all cases, the correct lug width is 16mm, tapering towards the buckle or deployant clasp.

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

To replace the strap on the Datejust 31, you will need a precision spring bar tool to remove the spring bars from the case lugs. It is advisable to work on a soft mat to avoid scratching the Oystersteel case. Original Rolex spring bars are generally reusable; if replacing them, ensure the correct length for the 31mm case is used.

Are there aftermarket straps compatible with the Rolex Datejust 31 178240-0019?

Yes, there are high-quality aftermarket straps compatible with the Datejust 31, provided they feature a 16mm lug width. Milano Straps and Casati Milano atelier produce bespoke straps in alligator, calf leather, shell cordovan and other fine materials, with stitching, keeper and buckle chosen by the client. The fit on the lugs is equivalent to that of the original Rolex bracelet.

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

The lifespan of a leather strap depends on the material, frequency of use and care. A quality alligator strap, kept away from water and heavy perspiration, typically lasts 3 to 5 years with regular use. Vegetable-tanned calf leather and shell cordovan have a more robust structure and withstand daily wear well. Casati Milano straps come with an 18-month guarantee 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