Strap for Speedmaster Moonwatch Co-Axial Titanium / Blue / Bracelet

The lug width is 21mm, a specific measurement for this model. It is not a mainstream standard like 20mm or 22mm, but a proportional dimension to the 44.25mm case that creates visual balance between the lugs and the wrist. It is possible to measure the lug width with a digital caliper by calculating the internal distance between the two pins of the spring bar.

The best strap depends on use and aesthetic preferences. Vegetable-tanned alligator offers natural material contrast with titanium and develops patina over time. Shell cordovan guarantees density and natural polish, ideal for those seeking a robust and long-lasting strap. Vegetable-tanned calf maintains constructive purity and engages minimally with titanium. Each material requires a quality deployant clasp for proper load transmission.

To change the strap, you need to access the spring bar pins. With a dedicated lever or small flat tool, push downward on the spring pin until the lateral end releases, freeing the pin itself. The old strap slides off the first lug. Next, insert the new strap into the first lug, position the spring pin, and gently push until the locking click. The operation requires care to avoid scratching the case.

All straps with 21mm lug width are compatible with the Speedmaster 311.90.44.51.03.001. On milanostraps.it you will find a selection of 21mm straps in alligator, shell cordovan, vegetable-tanned calf and technical fabrics, all customizable in size, initials and thread color. Compatibility is guaranteed by the lug width measurement, not by the strap brand.

The lifespan of a leather strap depends on material density, tanning method and use. Well-maintained vegetable-tanned alligator lasts 5-7 years of daily use. Shell cordovan, due to superior density, can reach 8-10 years. Vegetable-tanned calf has an average lifespan of 4-6 years. Natural aging (patina) is part of the beauty, not a defect. Casati Milano guarantees 18 months on all custom-made straps.