Rolex
Datejust 31 178158-0081— lug 16mm

The lug width of the Rolex Datejust 31 ref. 178158-0081 is 16 millimetres. This dimension is specific to the 31mm case and represents the distance between the two lugs where the strap attaches. It is essential to verify this measurement before purchasing a replacement strap, as an incorrect lug width (for example 14mm or 18mm) will not fit properly and will compromise both the aesthetics and functionality of the watch.

For the yellow gold Datejust 31, alligator leather in vegetable tanning represents the finest choice: the characteristic grains (parallel scales) naturally harmonise with the warmth of gold, and the leather develops an elegant patina with age. Alternatively, calfskin in box or grained finish offers understated sophistication, whilst shell cordovan (horse leather) guarantees superior durability. For versatility, a NATO strap in neutral colours or a vulcanised rubber strap allows for a more contemporary interpretation without compromising the watch's dignity.

Changing the strap on the Datejust 31 requires specific tools: a spring bar tool and a flat work surface. The procedure involves gently lifting the spring bars (one on each side) that secure the strap to the case lugs. Once released, the old strap slides out easily. The new strap (with a 16mm lug width) is inserted through the lugs and the spring bars are reinserted until they click into place. If you are uncertain, Casati Milano offers a bespoke strap-changing service with personalised leather consultation at their Milan atelier.

Yes, it is possible to fit aftermarket straps of quality onto the ref. 178158-0081, provided they respect the 16mm lug width specification. A bespoke strap crafted by a specialised atelier (such as Casati Milano) guarantees impeccable construction, controlled leather selection, and a deployante or buckle compatible with original Rolex spring bars. The quality of an aftermarket strap depends on the artisan's skill and leather sourcing: premium alligator or shell cordovan improves the tactile experience compared to mid-range alternatives.

Durability depends on leather type, tanning method, and wear rate. A quality alligator or calfskin strap in vegetable tanning lasts 5–10 years with ordinary care (avoid frequent wetting, protect from prolonged direct sunlight, clean with a dry cloth). Shell cordovan is more resilient (10–15 years). Factors accelerating wear include chlorine/salt water exposure, frequent perspiration, and excessive flexing. Casati Milano provides an 18-month warranty against manufacturing defects and offers guidance on leather maintenance to maximise longevity.