Strap for Portugieser Annual Calendar BFI London Film Festival

The lug width of the IWC Portugieser IW5035-05 is exactly 22 millimetres. This measurement is fixed and represents the distance between the two spring bar attachments protruding from the case. When searching for a compatible strap, you must verify that the width is precisely 22mm to ensure a tight fit without lateral play.

For the platinum Portugieser, the finest pairing is an alligator strap in medium brown with vegetable tanning, or black calf leather worked with natural tannins. Both options honour the nobility of the metal case and the aesthetic purity of the original 1930s design. Avoid sporty brands or synthetic materials that would clash with the formal language of the timepiece.

To change the strap, you must remove the spring bars that connect the strap to the case. Use a dedicated strap removal tool to gently compress the bar, freeing the first end of the strap. Repeat on the other side. Then insert the bars into the new strap, aligning the ends with the case attachments and pressing the bars into position until they click into place. If uncertain, contact a certified watchmaking atelier to avoid damaging the delicate platinum lugs.

Yes, absolutely. A high-quality aftermarket leather strap, crafted by a skilled artisan, can outperform many IWC original straps in terms of patina development, softness and longevity. The critical requirement is that the lug width be precisely 22mm, the leather be noble (alligator, cordovan, full-grain calf), and the stitching be hand-sewn with double thread. Avoid cheap industrial mass-produced alternatives that do not compare.

A full-grain leather strap, vegetable-tanned, typically lasts 5–8 years with daily wear, depending on frequency of use and maintenance. Shell cordovan can easily exceed ten years without structural failure. Longevity increases significantly if you rotate between several straps and protect the leather from excessive moisture and perspiration. Professional care—cleaning, conditioning, edge finishing—can double a strap's useful life.