Rolex
Datejust 31 178240-0019— lug 16mm

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.

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.

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.

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.

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.