Rolex
Datejust 31 178383-0013— lug 16mm

The lug width of the Rolex Datejust 31 reference 178383-0013 is 16 mm. This measurement must be taken with a calliper between the inner edges of the two lugs, where the strap attaches to the case. This is a specific dimension requiring straps manufactured precisely to this width to ensure a proper fit without lateral play.

For the Datejust 31 178383-0013 in yellow Rolesor, a vegetable-tanned alligator strap with a bombed profile is the most coherent choice: the grain texture echoes the fluted bezel, and the leather develops a personal patina over time. Smooth calf leather is the most versatile option for daily wear, while a nylon NATO or rubber strap suits sporting use, taking full advantage of the Oyster case's water resistance.

To replace the strap on the Datejust 31, you will need a spring bar tool — a forked-tip instrument used to compress the spring bars seated within the lugs. Insert the tip into the gap between the lug and the strap end, compress the spring bar inward and release one end at a time. Care should be taken not to scratch the yellow gold lugs: it is advisable to protect the case with masking tape during the procedure, or to entrust the operation to a watchmaker.

Yes. The aftermarket offers straps compatible with the 16 mm lug width of the Datejust 31, produced by specialist artisan workshops such as Casati Milano. These straps replicate the original dimensions — 16 mm at the attachment point, tapering towards the buckle — and are available in leather, nylon and rubber. It is important to verify that the strap thickness is compatible with the profile of the Oyster lugs to avoid any interference with the case.

The lifespan of a leather strap depends on the quality of the tanning, the thickness of the hide and frequency of use. A high-quality vegetable-tanned alligator strap, with proper care — periodic cleaning and application of a natural conditioner — can last between 3 and 6 years with daily wear. Smooth calf leather has a slightly shorter average lifespan. Casati Milano straps are covered by an 18-month warranty against manufacturing defects.