Strap for Portofino Automatic Stainless Steel / White - Railroad / Bracelet

The lug width of the IWC Portofino IW3513-37 is 18 millimetres. This dimension requires precise measurement: from the top edge of the spring bar to the bottom edge of the lug seat, the value must correspond exactly to 18mm. A variation of half a millimetre can compromise strap fit. We recommend measuring directly on the watch with a calliper before ordering.

For the Portofino IW3513-37 we recommend a dark brown or black alligator strap, or shell cordovan which develops a noble patina over time. Both materials respect the constructive elegance of the Portofino without competing visually with the case. For a formal profile, alligator with a steel deployant clasp is ideal; for those seeking versatility, vegetable-tanned calf offers a rough texture that emphasises the technical character of the watch.

Changing the strap requires the use of a spring bar tool and a stable surface. Position the watch with the case facing down, identify the two lateral spring bars (one on each side), insert the tool into the seat beneath the spring bar and press lightly upward to remove it. The new strap should be inserted by positioning one end of the lug first, then snapping the spring bar into the opposite seat. If you are not experienced with the procedure, entrust the work to a competent watchmaker to avoid damage to the case.

Yes, 18mm aftermarket straps are widely available online and from specialist suppliers such as milanostraps.it. Handcrafted full-grain leather straps, customisable in colour, stitch type and initials, represent the most versatile solution. Compatibility is guaranteed for any strap made to the 18mm lug width specification, regardless of material (alligator, calf, shell cordovan, vegetable tanning) and closure type (traditional, deployant).

A quality leather strap, made with vegetable tanning or natural alligator, has a lifespan of 3-5 years of daily use, extendable to 7-8 years with proper maintenance. Shell cordovan, thanks to its fibre density, can last over 10 years while acquiring a noble patina. Durability depends on exposure to UV rays, humidity and frequency of use. Casati Milano provides an 18-month warranty on its handcrafted straps, covering manufacturing defects and premature wear due to manufacturing faults.