Strap for WilliamsF1 Team Day Date 40.5 Stainless Steel / Blue / Rubber

The lug width of the Oris Williams 01 635 7560 4165-07 4 25 01 is 35 mm. This measurement refers to the linear distance between the two attachment points on the case where the strap is inserted. It is essential to verify this exact dimension before purchasing an aftermarket strap to ensure compatibility without lateral play or forcing when inserting the spring bars.

The ideal strap depends on intended use. For formal and refined daywear contexts, we recommend alligator leather or vegetable-tanned calf: both maintain the agonistic elegance of the model. For sports environments or frequent alternatives, a NATO strap in polyamide offers ease of changing and minimal maintenance. For water activities, FKM rubber guarantees impermeability and stability. All straps must feature a 35 mm lug width.

Strap replacement is performed by inserting a dedicated tool (spring bar tool) into the lateral spaces between the case and the lugs, releasing the spring pins that secure the current strap. Once the pins are extracted, remove the old strap and insert the new one, ensuring that the pin passage holes align perfectly with the case attachment. Press with gentle firmness until you feel the click of closure. Never force: unusual resistance indicates misalignment.

Yes, any quality strap with a 35 mm lug width is compatible with this Oris model. Milano Straps offers a specialised collection of artisanal straps in various finishes (alligator, vegetable-tanned calf, NATO, rubber) specifically dimensioned for this lug width. The construction quality of the aftermarket strap is crucial: a poorly manufactured strap results in accelerated case wear and poor wearing comfort.

The durability of a leather strap depends on intensity of use, climatic conditions, and material quality. A vegetable-tanned calf strap, worn daily in temperate conditions, typically offers 3–5 years of use before visible wear appears (fraying edges, thinning in the fold zone). Exposure to moisture, salt air, or excessive heat shortens this interval. Alligator straps, being naturally more robust, can exceed 5–7 years with regular maintenance. FKM rubber, conversely, offers superior durability (8–10 years) but requires periodic cleaning to maintain elasticity.