Rolex
Datejust 31 178384-0017— lug 16mm

The Rolex Datejust 31 reference 178384-0017 has a lug width of 16mm. This measurement refers to the internal distance between the two lugs of the case and is the essential parameter for selecting any compatible aftermarket strap.

For the Datejust 31 in white gold and steel, a fine-grain alligator belly-cut strap or a shell cordovan strap are the most coherent choices for the formal character of the watch. A burgundy or navy blue alligator strap in 16mm enhances the Fluted bezel and dial without overloading the overall aesthetic. For more casual or sport use, a technical nylon NATO or vulcanised rubber strap preserves the water resistance of the Oyster case.

To replace the strap on the Datejust 31, a spring bar tool with a 1.0–1.2mm tip diameter is required. The original Rolex 16mm spring bars are released by applying gentle pressure at the tapered end of the tool into the lug slot. It is advisable to work on a soft surface to avoid scratching the case, and to replace spring bars showing signs of wear or deformation.

Yes. Aftermarket straps compatible with the Datejust 31 ref. 178384-0017 must have a 16mm lug width and, ideally, a curved or semi-curved end profile to fit the original lug geometry. Milano Straps and the Casati Milano atelier produce bespoke handcrafted straps in various leathers and finishes, with dimensional compatibility verified against the original case.

The lifespan of a handcrafted leather strap depends on the material and frequency of use. A vegetable-tanned alligator strap, with routine care, retains its structural and aesthetic integrity for 3–5 years of regular wear. Shell cordovan, due to the dense fibre structure of the horse's subcutaneous layer, tends to last over 5 years while developing a distinctive patina. Prolonged exposure to water, perspiration and UV light accelerates deterioration; it is recommended to rotate straps and treat them periodically with a quality leather conditioner.