Strap for Pilot's Watch Spitfire Double Chronograph Stainless Steel / Silver / Spanish / Strap

The lug width of the IWC Pilot IW3713-45 is precisely 21mm. This measurement represents the ideal proportion between the case diameter (42mm) and the visual balance on the wrist. You can verify it by inserting a digital calliper between the lug attachments: the internal distance must correspond to 21mm to ensure complete compatibility with standard artisanal straps.

The ideal strap depends on your usage and aesthetic preference. For the historical pilot watch combination, alligator in a tight grain pattern and black finish reflects the heritage. If you prefer a softer leather with natural patina development, vegetable-tanned calf is excellent. For absolute durability and water resistance, FKM rubber in matte black offers superior grip. Shell cordovan, finally, is the premium choice for those seeking sophisticated aesthetics, though it requires greater maintenance.

To change the strap, remove the case from the lugs using a flat spring bar tool. Insert the tool into the small hole present under the lug, gently pushing upward to release the spring pin that holds the strap. Once the old strap is removed, align the new strap (21mm width) with the two attachment points and reinsert the spring pin until you hear a click. Ensure the strap is firmly secured before wearing the watch.

Yes, provided the strap is constructed natively for 21mm lug width. High-quality artisanal straps in alligator, calf, and rubber are fully compatible. Avoid adapters that reduce width as they compromise the original aesthetics and create additional mechanical wear points. The key is to verify that the strap source certifies the exact lug width, preferably with laboratory measurement documentation.

Durability depends on the leather type and usage frequency. A superior alligator strap, worn daily, provides 3-4 years before replacement is necessary, with visible patina that improves during the final 6-12 months. Vegetable-tanned calf tends to last 2-3 years before showing signs of wear at the edges. FKM rubber has a longer lifespan (4-5 years) if kept clean and protected from prolonged direct sunlight. Rotating between multiple straps significantly extends the lifespan of each.