Strap for Portofino Chronograph MecaQuartz Stainless Steel / White / Calf

The lug width of the IWC Portofino IW3731-05 is exactly 18 millimetres. This measurement is taken between the centres of the spring bar attachment points. Always verify with a digital calliper before purchase, as tolerances finer than 0.1 millimetres can cause insertion difficulties.

For the Portofino IW3731-05 in yellow gold, we recommend natural alligator leather, which amplifies the warm tone of the metal without creating visual competition. Calfskin with vegetable tanning develops a patina over time that harmonises with aged gold. Shell cordovan creates an elegant contrast with its burgundy tone. We do not recommend NATO straps, as the raw polypropylene clashes with the nobility of yellow gold.

To change the strap on the Portofino IW3731-05, you will need a spring bar removal tool. Insert the bifurcated tip of the tool into the small lateral hole beneath the lug and gently press downward to retract the spring bar. Simultaneously, extract the old strap. Repeat on the opposite end. To install the new strap, align the terminals with the spring bars, press the strap into position, and verify that both attachments click securely.

Yes, any strap with an 18-millimetre lug width is compatible with the Portofino IW3731-05. Bespoke artisanal straps offer the opportunity to select noble materials (alligator, shell cordovan, vegetable-tanned calfskin) and custom configurations, including personalised length and deployant clasp choice. Always confirm the lug width is 18 millimetres with the manufacturer.

Durability depends on material and usage. Alligator leather, vegetable-tanned or shell cordovan straps last 4–7 years with daily wear, developing a pleasant ageing patina. Vegetable-tanned calfskin has similar longevity (4–6 years). FKM rubber exceeds 10 years without aesthetic degradation. In dry climates, air-dry the strap after accidental moisture exposure. To extend lifespan, store the strap in a cool, dry location away from direct heat sources.