Strap for Datejust 31 Stainless Steel / Jubilee / Green

The Rolex Datejust 31 ref. 278240-0012 has a lug width of 16mm. This measurement is taken internally between the two lugs using a digital calliper, parallel to the case. It is specific to the 31mm variant and differs from the Datejust 36mm (20mm) and 28mm (13mm) versions.

For the stainless steel Datejust 31, an alligator belly strap or a vegetable-tanned calf leather strap are the most coherent choices. The alligator grain complements the polished case finishing, whilst calf leather develops a personal patina over time. For sporting or summer use, a NATO nylon or vulcanised rubber strap offers water resistance without compromising the aesthetic of the 31mm case.

Strap replacement requires a spring bar tool to remove the spring bars from the lugs. It is advisable to rest the case on a watch cushion to avoid scratching the 904L Oystersteel. Press the notched end of the spring bar with the tool to compress and release it from the lug hole. The operation does not require professional equipment but should be performed carefully to avoid damaging the lugs.

Yes, aftermarket straps with a 16mm lug width are fully compatible with the Datejust 31 ref. 278240-0012. Handcrafted production allows tolerances of ±0.3mm from the nominal measurement, ensuring a precise fit. On milanostraps.it you will find models in alligator, calf leather, shell cordovan, NATO and rubber, all made to measure for this configuration.

Longevity depends on the material and frequency of wear. A quality alligator strap, properly maintained with specialist leather conditioner and kept away from water, typically lasts 2–4 years with regular use. Vegetable-tanned calf leather has a similar lifespan but develops a patina that improves its appearance over time. Shell cordovan, owing to the density of its fibres, can exceed 5 years. All Casati Milano straps carry an 18-month warranty against manufacturing defects.