Strap for Datejust 31 Stainless Steel Domed / Oyster / Rhodium Roman

The Rolex Datejust 31 ref. 178240-0006 has a lug width of 16mm. This measurement is taken internally between the two lugs using a digital calliper with the spring bar removed. An acceptable tolerance for aftermarket straps is ±0.2mm to ensure correct spring bar fitment without lateral play.

For the steel Datejust 31, a 16mm hornback alligator strap in vegetable-tanned leather offers the most coherent pairing with the watch's formal register. Box calf leather is preferable for intensive daily use, while nylon NATO straps are appropriate for sporting contexts. The choice depends on the dial colour: warm-toned dials pair well with cognac or havana leathers, while cool-toned dials suit navy or dark grey.

To replace the strap on the Datejust 31, you will need a spring bar tool with a fine tip. Insert the tip into the notch on the side of the lug, compress the spring bar and slide it out. Repeat on both lugs. To fit the new strap, compress the spring bar on one side of the strap, insert it into the opposite lug, then release it into place. No professional tools are required, but it is advisable to work on a soft surface to prevent scratches to the case.

Yes. Any strap with a 16mm lug width and standard length (approximately 105mm + 75mm for average wrists) is compatible with the Datejust 31. For the Oyster lugs of this model, straps with straight or slightly pre-curved ends for Rolex 16mm are preferable, ensuring a flush fit against the case back profile. Milanostraps.it offers a curated selection of handcrafted 16mm straps for this reference.

The lifespan of a leather strap depends on the quality of the tanning process, frequency of wear and maintenance. A quality vegetable-tanned alligator strap, worn regularly and conditioned with a leather cream every 3–4 months, will retain structural and aesthetic integrity for 3–5 years. Calf leather typically lasts 2–3 years with intensive use. Perspiration and moisture are the primary degrading agents; it is advisable to rotate straps and avoid wearing leather during sport or in high-humidity conditions.