Strap for WilliamsF1 Team Day Date 40.5 Stainless Steel / Black - Yellow / Rubber

The lug width of the Oris Williams 01 635 7560 4142-07 4 25 01 is 35 millimetres. This measurement represents the distance between the two spring bars that hold the strap, measured from inside to inside. This is an unconventional dimension that requires bespoke-made straps to ensure correct fit and proportions.

We recommend an alligator strap in vegetable tanning with cognac or dark brown tones, which amplifies the racing aesthetic whilst maintaining sophistication, or a NATO strap in polyamide for daily practicality and military heritage. A vegetable-tanned calf leather offers balance between elegance and durability. FKM rubber is ideal for humid environments and sport activities. Your choice depends on the intended use and personal preference for patina development over time.

To change the strap, locate the spring bars connecting the strap to the case at 3 o'clock and 9 o'clock positions. Use a spring bar remover tool to gently remove the bars, taking care not to scratch the case. Once the bars are removed, extract the old strap and insert the new one, ensuring the bars snap firmly into position. If you are unfamiliar with this procedure, we recommend consulting a professional watchmaker.

Yes, aftermarket straps manufactured specifically with a 35mm lug width are fully compatible with the Oris Williams 01 635 7560 4142-07 4 25 01. It is essential to verify that the width is precisely 35 millimetres and that the leather thickness does not exceed 1.2–1.4 millimetres, to ensure the strap inserts correctly into the spring bars without forcing. Milano Straps manufactures custom straps for this specific dimension.

The lifespan of a leather strap depends on the tanning method, daily use, and environmental conditions. High-quality vegetable-tanned leather can last 2–3 years with moderate use, developing an appealing patina over time. Frequent exposure to humidity, perspiration, and sunlight accelerates wear; the leather dries out and may crack. A NATO strap or rubber strap is more durable (4–5 years), whilst high-quality alligator can exceed 5 years whilst maintaining structural integrity.