Rolex
Datejust 31 178240-0015— lug 16mm

The lug width of the Rolex Datejust 31 178240-0015 is 16 millimetres. This dimension is measured between the inner points of the two lateral lugs and is proportionally designed for the 31mm case. Respecting this specification is essential to ensure proper strap installation without mechanical stress on the lugs.

For the stainless steel Datejust 31, Mississippi alligator is the most harmonious choice: its regular grain and silvery patina reflect the 904L case finishing. American shell cordovan develops an amber patina that brings warmth, whilst vegetable-tanned Italian calf offers natural ageing and visible character for those who appreciate it.

Changing the strap on a Datejust 31 requires an appropriate spring bar tool. Position the watch with the lugs facing upward, insert the tool into the lateral access hole of the lug, gently lift the internal spring, and withdraw the case bar. Repeat on the other side. The new strap must have a 16mm lug width for secure, play-free installation.

Yes, provided the lug width is precisely 16 millimetres. Artisanal straps in alligator, shell cordovan, calf, and vegetable-tanned leather are compatible. It is advisable to verify that the strap has been constructed with quality spring bars, as the Rolex requires precise manufacturing tolerances to prevent damage to the stainless steel 904L lugs.

The lifespan of a leather strap depends on usage and construction quality. A premium alligator or shell cordovan strap, with proper maintenance (regular cleaning, protection from excessive moisture), can last 5–8 years. A softer vegetable-tanned calf typically offers 3–5 years of useful life. Visible ageing of the leather is an intentional characteristic, not a defect.