Rolex
Datejust 31 178241-0040— lug 16mm

The Rolex Datejust 31 reference 178241-0040 has a lug width of 16mm. This measurement is taken between the two metal lugs at the strap attachment point, not across the outer edge of the case. It is specific to this 31mm variant and differs from the 20mm lug width of the Datejust 36.

For the Datejust 31 in Rolesor Everose, the most suitable materials are alligator belly or hornback in warm tones (bordeaux, tobacco, dark brown), shell cordovan for those seeking an evolving patina over time, or vegetable-tanned leather for breathability and natural adaptation to the wrist. A butterfly deployant clasp ensures comfort and even pressure distribution.

Replacing the strap on a Datejust 31 requires a fine-tipped spring bar tool to release the spring bars from the lugs. The operation should be carried out with care to avoid scratching the Oystersteel or Everose gold lugs. Rest the case on a soft cloth and work under adequate lighting. If in doubt, consult a watchmaker or the Casati Milano atelier.

Yes, quality aftermarket straps for a 16mm lug width are available and compatible with the Datejust 31 178241-0040. It is essential to verify that the attachment width is exactly 16mm and that the spring bar length suits the depth of Rolex lugs. Milano Straps offers a dedicated selection at milanostraps.it, with bespoke options crafted by the Casati Milano atelier.

The lifespan of a leather strap depends on the material, frequency of use, and maintenance. A quality alligator strap, used in rotation and kept away from moisture, can last between 3 and 7 years while retaining structural and aesthetic integrity. Shell cordovan tends to last longer due to its dense fibre structure. Vegetable-tanned leather improves with age when treated with appropriate conditioners. A sound keeper and sturdy buckle further extend the strap's life.