Strap for WilliamsF1 Team Day Date 40.5 Stainless Steel / Black / Bracelet

The lug width of the Oris Williams 01 635 7560 4164-07 8 25 01 is 35mm, measured as the net distance between the two case lugs. This non-standard width reflects the squared proportion of the 40.5mm case and ensures balanced aesthetics. To measure correctly, position a calliper perpendicular to the case shoulders, excluding the case indent at the lugs.

The ideal strap depends on daily usage. For formal elegance, black or dark grey alligator offers dynamic texture that emphasises the racing character. For everyday practicality, vegetable-tanned calf leather ensures superior durability and develops natural patina over time. For maritime or humid environments, a nylon NATO maintains aesthetic severity whilst providing waterproofness. FKM rubber is the ultimate choice for those prioritising absolute practicality.

To change the strap, use a spring bar removal tool or a robust toothpick. Gently push the spring bar from beneath the case to extract it completely. Insert the new 35mm strap by aligning the holes with the lugs and push until it clicks firmly into position. Ensure the strap is balanced on both sides before wearing the watch.

All straps with 35mm lugs are compatible with the Williams. Milano Straps offers a specialised collection of 35mm straps in alligator, calf leather, NATO and rubber. Ensure the strap explicitly declares 35mm width, as constructive tolerances even of 0.5mm influence fit with the case. Prefer straps with thickness between 3.5 and 4.5mm to maintain harmonious visual proportions.

Longevity depends on material and usage. Vegetable-tanned calf leather lasts 3-4 years in daily use with proper maintenance (dry after water exposure, avoid prolonged humidity). Alligator, being thicker and more compact, easily reaches 4-5 years. Maximum longevity (5-7 years) is achieved with rubber or NATO, materials unaffected by moisture. Protect the strap from direct sunlight exposure and apply protective balm every 6 months to slow natural leather ageing.