Strap for Datejust 31 Yellow Gold / Domed / Champagne / President

The Rolex Datejust 31 reference 278248-0040 has a lug width of 16mm. This measurement is taken with a digital calliper placed between the inner faces of the lugs, perpendicular to the strap axis. 16mm is a non-standard size — distinct from the more common 18mm or 20mm — so straps must be sourced specifically for 16mm lugs to ensure a correct fit.

For an 18-carat yellow gold case measuring 31mm, a smooth alligator strap in warm tones — bordeaux, tobacco, navy — offers the most formally coherent pairing. Full-grain vegetable-tanned calfskin suits daily wear with the benefit of developing an individual patina over time. Shell cordovan provides the greatest structural density and edge durability. In all cases, the strap must measure exactly 16mm at the lug attachment, with proportionate thickness and stitching relative to the 31mm case diameter.

Strap removal requires a spring bar tool — ideally with a forked tip to avoid scratching the yellow gold lugs. The Datejust 31 uses standard 1.5mm-diameter spring bars. Work on a watch cushion with the case dial-side down to prevent scratches to the crystal and bezel. If unfamiliar with the process, it is advisable to consult a watchmaker or visit the Casati Milano atelier for a professional fitting.

Yes. The aftermarket offers leather, rubber, and textile straps with a 16mm attachment compatible with this reference. Milano Straps provides a curated selection of handcrafted 16mm straps with shaped ends designed to integrate correctly with the Datejust 31 lugs. It is important to verify that the strap thickness at the attachment does not exceed 3.5mm to ensure it sits flush under the lugs.

Longevity depends on the material and conditions of use. A quality alligator strap, worn on rotation and properly maintained, retains structural and aesthetic integrity for 3 to 5 years. Vegetable-tanned calfskin develops patina and typically lasts 2 to 4 years with regular conditioning. Shell cordovan often exceeds 5 years due to the density of its fibre structure. Prolonged exposure to perspiration and water significantly shortens the service life of any leather strap; it is recommended to remove leather straps before sporting activities.