Rolex
Datejust 31 178240-0032— lug 16mm

The lug width of the Rolex Datejust 31 ref. 178240-0032 is 16mm. This measurement refers to the space between the two lugs (spring bar attachment points) of the case. Any compatible strap must respect this dimension for correct fitting and proper aesthetic proportion. It is important not to confuse lug width with the visible width of the strap when worn: the former is the technical attachment dimension, the latter is what you see on the wrist.

For the Datejust 31 in stainless steel, alligator represents the reference choice: its natural grain, soft feel, and the patina it develops over time create a strap that ages gracefully. Alternatively, calf leather with vegetable tanning offers authentic ageing and superior daily versatility. For those seeking practicality and versatility, a rubber strap with stainless steel deployante clasp provides sporty comfort whilst maintaining the seriousness of the case. Your choice depends on your lifestyle and daily watch usage.

Strap replacement requires a spring bar tool (a small forked instrument that compresses the internal spring of the lug). Position the spring bar tool into the slots on the side of the lug, gently compress the spring, then slide the old strap out of the lugs. Repeat with the new strap, ensuring the retention spring clicks into place correctly. If you are inexperienced, entrust this task to a watchmaker: the risk of scratching the case during this operation is real for those without experience.

Yes, absolutely. A high-quality artisanal strap with 16mm lug width is perfectly compatible with your Datejust 31. The key is choosing a craftsman who respects finishing standards, leather softness, and constructive precision equal to the original strap. Brands like Casati Milano offer bespoke straps in alligator, calf, and other materials that equip the Datejust 31 with fresh personality whilst maintaining serious construction standards. An aftermarket strap does not void your watch warranty if the change is executed correctly.

A leather strap's lifespan depends on tanning quality, daily usage, and maintenance. A high-quality alligator strap typically lasts 3–5 years with moderate daily wear; vegetable-tanned calf lasts 2–4 years. Constant exposure to perspiration, fresh water, and humidity reduces lifespan; regular cleaning with a soft dry cloth and alternating with a second strap significantly extends life. Casati Milano offers an 18-month warranty against manufacturing defects, but periodic strap replacement is a natural aspect of owning a classic watch — much like changing an everyday garment.