Strap for Portofino Automatic 37 Red Gold - Diamond / Silver

The lug width of the Portofino IW6586-03 is 18 millimetres. This specific technical measurement refers to the distance between the two horizontal pins where the watch strap inserts into the case. It is a relatively uncommon measurement in contemporary IWC catalogues, positioned between the 16mm and 20mm standards, ideal for cases with a diameter around 37–39mm. Always verify compatibility by measuring with a calliper from the inside of one pin to the inside of the other.

For the Portofino IW6586-03 in red gold, straps in superior-grade alligator leather, vegetable-tanned calf, or shell cordovan are recommended. Dark brown or cognac alligator creates elegant colour continuity, whilst a burgundy calf produces a sophisticated aesthetic tension with the golden reflections of the case. Shell cordovan, though requiring a learning curve in maintenance, develops a crystalline patina over time that further amplifies the warmth of the case. Avoid sporty materials such as NATO, which would contradict the classical spirit of the watch.

Strap replacement requires extraction of the lug pins using a dedicated tool (spring bar remover), available at any watch retailer. Position the tip of the tool in the small recess on the side of the spring, apply light vertical pressure to release the pin from its seat, then extract the pin and slide off the previous strap. Insert the new strap by aligning the 18mm holes with the pins, then reinsert the pins into their seat until you hear a click. Verify that the strap is securely anchored before wearing the watch.

Yes, you may use aftermarket straps provided they respect the 18mm lug width specification. Artisanal straps from specialist suppliers with luxury sector experience often offer superior construction quality and material selection compared to OEM straps. Before purchase, always verify 18mm compatibility and prefer makers who declare warranty on manufacture and stitching. An aftermarket strap does not compromise IWC warranty validity unless damage is directly caused by incorrect installation.

The lifespan of a leather strap depends on the material selected, frequency of use, and environmental conditions. High-quality alligator leather, with vegetable tanning and natural thread stitching, maintains structural functionality for 3–5 years of daily wear, though patina and appearance evolve continuously. Traditional aniline calf has similar durability but is more vulnerable to direct moisture. Shell cordovan, if properly maintained, may last 5–7 years whilst retaining structural integrity. Regardless of material, irreversible wear symptoms include stitch separation, leather thinning, or strap breakage at the buckle point. A well-maintained strap (periodically cleaned and protected from excessive humidity) consistently exceeds the declared average lifespan.