Strap for Williams Day Date 42 Stainless Steel / Blue / Rubber

The lug width (misura ansa) of the Oris Williams 01 735 7740 4155-07 4 24 54FC is exactly 24mm. This measurement refers to the distance between the two attachment holes on the case where the spring bars are inserted. To measure accurately, remove the original strap by sliding out the elasticated pins and measure the distance between the lugs with a digital calliper: the result will be precisely 24mm. This dimension was conceived by Oris to maintain correct visual proportions between the 42mm case and the strap.

The ideal strap depends on your intended use and the aesthetic personality you wish to activate. An alligator strap with vegetable tanning in cognac or medium-brown tones emphasises the formal elegance of the dial and tachymetric bezel. For a sportier style, a polyamide NATO in navy blue or black offers durability and rapid interchangeability. If you prefer low maintenance, a black box calf ages gracefully while developing personal patina. For aquatic environments or summer wear, an FKM rubber strap in black guarantees total waterproofing and straightforward cleaning. MilanoStraps offers 24mm-compatible straps in all these materials, customisable in colour and length.

Strap replacement on the Williams is a straightforward operation. You will require a spring bar tool (a small implement with a forked tip) available from any jeweller or online retailer. Position the dial facing downward and insert the forked tip of the tool into the small aperture present at one end of the strap, pressing gently downward until the internal spring bar retracts. The strap should separate cleanly. Repeat on the opposite side. Install the new strap by aligning the attachment holes with the case and pushing the spring bar until it clicks into position. If the new strap is in natural leather, allow it 24-48 hours of wear before making a final comfort assessment.

Yes, any strap with a 24mm lug width is compatible with the Williams. Aftermarket straps from specialised manufacturers (such as the handcrafted offerings from MilanoStraps) are frequently constructed with superior thickness and finishing relative to original straps, ensuring a more solid fit and extended durability. Always verify that the strap carries a 24mm width specification and that the spring bars are installed correctly. Premium straps often feature an adjustable deployante (folding clasp with snag mechanism), which increases wearing comfort and security.

Leather strap longevity depends on material grade and frequency of wear. A quality vegetable-tanned alligator strap, worn 5-6 days per week with correct maintenance, typically lasts 3-5 years. Box calf leather offers slightly shorter durability (2-4 years) but ages more gracefully, developing unique patina. To maintain your Williams, clean the strap weekly with a soft, dry cloth, avoid prolonged contact with water (particularly saltwater or chlorine), and apply natural leather conditioner every 6-8 months if the strap appears dry. Store the watch away from direct heat sources. Should the strap deteriorate, a replacement with an artisanal strap represents an opportunity to explore a new tone or material entirely.