Strap for Datejust 31 Stainless Steel / Oyster / Blue - Roman

The lug width (also called 'lug size' or 'case width') of the Rolex Datejust 31 278240-0017 is 16mm. This measurement is taken between the spring bars—the steel pivots that connect the strap to the case lugs. Do not confuse lug width with material thickness: 16mm is the exact space the strap must occupy under the lugs.

For a stainless steel Datejust 31, we recommend vegetable-tanned alligator (timeless elegance and durability), shell cordovan (develops rich patina over 2–3 years), or smooth calf in neutral tones (tobacco brown, black, bordeaux) for daily wear. The choice depends on your intended use: everyday use favours calf leather, formal occasions suit alligator, and summer weather suits linen NATO straps. All must be 16mm lug width.

Strap changes require a spring bar tool and precision. Position the watch with one lug facing upward, insert the tool's flat tip into the hole beneath the spring bar pin, lift gently to release the spring mechanism, and slide the pin out. Repeat on the opposite side. When installing your new 16mm strap, ensure both barrels of the strap engage with the pins before fully releasing the spring tool. Work slowly to avoid scratching the lugs.

Yes, provided it respects the 16mm lug width specification. Any quality artisanal strap (leather, rubber, fabric) bearing 16mm lug width is compatible. We recommend manufacturers offering dimensional precision and refined finishing. Undersized straps (15.5mm) will create play; oversized straps (16.5mm) will not fit properly. Always verify specifications before purchase.

Leather strap longevity depends on use frequency, tannage, and maintenance. A quality artisanal alligator or cordovan strap lasts 3–5 years with moderate daily wear (5–6 days weekly), and up to 7–8 years with occasional use. Smooth calf is more delicate: approximately 2–3 years. A stainless deployante buckle reduces internal leather friction. Store the strap away from excessive humidity and apply neutral balm occasionally to maintain suppleness.