IWC · Portofino

Strap for Portofino Automatic Stainless Steel / White - Roman / Strap

Takes 18 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width

18mm
Lug width18 mm
Case diameter34 mm
ReferenceIW3513-34
FamilyPortofino
MovementIWC caliber 37521 hours, minutes, seconds, world time | date
Year1988 - 2002
CaseStainless Steel

Spring bar

Swiss Standard universal spring bars

The right category for this model · 316L steel, all lug widths 13–26 mm

Straps for the Portofino IW3513-34

Selected for the 18 mm lug width

All 18 mm straps →

The Portofino IW3513-34, seen from the bench

The Portofino IW3513-34 is a 34mm automatic watch with stainless steel case and white dial featuring Roman numerals. It houses the caliber 37521 manual-winding movement, offering hours, minutes, seconds, World Time function, and calendar complication. The case features satin-finished sides and polished caseback, with characteristic Portofino curved lines. Lug width is 18mm, matching the classical proportions of this model from the Portofino collection.

Frequently asked questions

What is the lug width of the IWC Portofino IW3513-34?

The lug width is 18mm, which is the distance between the spring bars that connect the strap to the case. This dimension is specific to the 34mm Portofino models and ensures the proportional balance that characterises this timepiece.

Which strap is recommended for the IWC Portofino IW3513-34?

To enhance the polished stainless steel case, we recommend straps in dark alligator (black, chocolate brown) or aged shell cordovan. Vegetable-tanned calf leather offers an excellent middle ground. For summer wear, a grey pearl or navy cotton NATO remains elegant without compromise.

How do I change the strap on my IWC Portofino IW3513-34?

Locate the spring bars (small metal elements at the case ends where the strap attaches). Using a dedicated tool or fine screwdriver, remove the spring bar by pushing it inward. Extract the old strap, thread the new one aligning the holes, then reposition the spring bar until fully secured.

Can I use aftermarket straps on my IWC Portofino IW3513-34?

Yes, any strap with an 18mm lug width is compatible. Artisanal quality straps guarantee superior durability and aesthetics compared to generic replacements. Always choose noble leathers and robust construction to protect your watch investment.

How long does a natural leather strap last on an IWC Portofino?

A premium leather strap (alligator, shell cordovan, vegetable-tanned calf) typically lasts 3–5 years with moderate use. Durability depends on maintenance level, water exposure, and lifestyle. Natural ageing of the leather is desirable and increases aesthetic value over time.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

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Casati Milano · Via XX Settembre 15, Milan · by appointment only