Rolex · Datejust 31

Strap for Datejust 31 Yellow Gold Diamond / Oyster / Steel Roman

Takes 16 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width16 mm
Case diameter31 mm
Reference178288-0085
FamilyDatejust 31
MovementRolex caliber 2235 hours, minutes, seconds | date | chronometer
CaseYellow Gold

Spring bar

Spring bars for Rolex

The right category for this model · choose the 16 mm size

Straps for the Datejust 31 178288-0085

Selected for the 16 mm lug width

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The Datejust 31 178288-0085, seen from the bench

The Datejust 31 represents the female version of the Rolex Datejust collection, characterized by a 31mm diameter case. It features the automatic caliber 2235 with hour, minute, second and date functions, certified as a chronometer. The lugs measure 16mm in width to accommodate the strap.

Frequently asked questions

What is the lug width of the Rolex Datejust 31 178288-0085?

The lug width (misura ansa) of the Rolex Datejust 31 178288-0085 is 16mm. This is the distance between the two spring bars that connect the strap to the case lugs. It is a Rolex standard specific to the 31mm model and is essential for ensuring a perfect fit without play or gaps.

What is the best strap material for the Datejust 31 178288-0085?

For a Datejust 31 in yellow gold, alligator (Mississippi or Nile) is the classic and reliable choice, available in brown, cognac, or burgundy tones. Shell cordovan is exceptional for those seeking durability and a unique natural patina. Vegetable-tanned calf offers softness and sustainability, developing character over time. Structured rubber is ideal for everyday versatility.

How do you change the strap on the Rolex Datejust 31 178288-0085?

The strap is changed by extracting the spring bars from the case lugs using a dedicated spring bar tool. Position the tool in the small groove of the bar, push toward the centre of the case and the bar retracts, allowing extraction. Repeat on the other side, then position the new strap by aligning the holes and re-inserting the spring bars until they click into place.

Is an aftermarket strap compatible with the Datejust 31 178288-0085?

Yes, provided the strap is constructed for a 16mm lug width. Compatibility depends on the exact width of the lug attachment points (16mm) and the build quality—whether leather, rubber, or metal—must be of a standard comparable to Rolex to avoid compromising the watch's aesthetics. We recommend bespoke artisanal straps made to specification to guarantee precision in proportions and finishing.

How long does a leather strap last on the Rolex Datejust 31 178288-0085?

A quality leather strap (alligator, shell cordovan, vegetable-tanned calf) lasts between 3 and 7 years depending on daily use and maintenance. Alligator and shell cordovan are more resistant and can exceed 5–7 years. Critical factors are: sun exposure, humidity, perspiration, and frequency of wear. Proper storage (away from direct light and damp conditions) significantly extends strap life. Casati Milano straps include an 18-month warranty against manufacturing defects.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

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Casati Milano · Via XX Settembre 15, Milan · by appointment only