Rolex
Datejust 31 178241-0002— lug 16mm

The lug width is 16mm—the precise distance between the lugs that anchor the strap to the case. This specification is particular to the Datejust 31 and must be measured accurately between the internal walls using a precision tool such as a digital calliper.

Genuine alligator in dark bordeaux or black tones complements the rose gold-steel two-tone case, creating sophisticated visual contrast. Alternatively, vegetable-tanned calf leather with natural patination develops dignified ageing whilst maintaining formal elegance without chromatic excess.

Strap replacement requires specific tools: a spring bar tool to remove the elastic pins from the lugs, a scratch-free work surface, and the new strap with 16mm diameter spring bars. Consult a specialist watchmaker if you lack experience—the risk of scratching the case with improper technique is substantial.

Yes, bespoke leather straps crafted by ateliers such as Casati Milano—with carefully selected hides and calibrated deployante—offer reliability and aesthetic quality comparable to genuine Rolex originals. The 16mm lug width is non-negotiable; beyond that, design selection is personal choice.

Vegetable-tanned calf leather typically endures 3-5 years of regular use before requiring restoration. Genuine alligator, owing to its density and fibrous structure, can exceed 7-10 years. Humidity exposure, UV radiation, and frequency of wear accelerate natural leather ageing.