Rolex
Datejust 31 278275-0039— lug 16mm

The lug width of the Rolex Datejust 31 reference 278275-0039 is 16 millimetres. This measurement represents the external distance between the two lugs protruding from the case that accommodate the spring bars and straps. It is essential to respect this specification when purchasing an aftermarket strap to ensure proper fit and prevent undesirable movement during wear.

For a Datejust 31 in Everose gold, the ideal strap is alligator leather with vegetable tanning, which develops a natural patina in harmony with the rosy tone of the case. Alternatively, Hermès calf or shell cordovan offer understated elegance and dignified ageing. Synthetic rubber or bonified leather straps compromise the perceived value of the watch and do not age aesthetically.

Changing the strap on a Datejust 31 requires a spring bar tool—a specialised instrument with a spatula tip that allows compression of the internal spring mechanism. Position the tool on one of the two lugs, apply controlled pressure to retract the lug inside the spring, remove the used strap, and insert the new one. Always work on a soft surface to avoid scratching the case and move fluidly to prevent stress on the lugs.

Yes, provided the aftermarket strap respects the 16-millimetre lug width. However, not all manufacturers maintain precise mechanical tolerances: straps manufactured with variations of ±0.3 millimetres may result in a loose or overly tight fit. We recommend relying on specialist artisans such as Casati Milano, who guarantee millimetre-precision engineering and premium materials.

A high-quality natural leather strap, subject to moderate use (3–4 days per week), has an average lifespan of 4–6 years. Vegetable tanning enables superior longevity compared to industrial chrome tanning. Factors such as humidity, sun exposure, and frequency of strap changes influence durability. An artisanally crafted strap with rigorous quality control, such as those from Casati Milano, can reach 8 years of daily use thanks to leather density and superior craftsmanship.