Strap for Motorsport Automatic Chronograph PVD / Red Bezel / Black / Rubber

The lug width of the Formex Motorsport 3100.4.8122.910 is 25 millimetres. This is a non-standard, considerable lug width typical of large racing chronographs (46.50mm case diameter). It ensures harmonious proportions and secure fit on robust wrists.

For the Formex Motorsport 3100.4.8122.910, we recommend black or dark brown alligator for formal wear, or vegetable-tanned calf leather to develop a rich patina over time. For sporting or nautical use, a grey or military green NATO, or dark grey rubber, reflects the racing philosophy of the chronograph.

Strap replacement is performed via the lateral lugs of the case. Use a spring bar tool to gently push the lug spring towards the centre, creating sufficient space to remove the old strap. Insert the new strap in the same position, ensuring both sides are securely locked. For maximum security, we recommend performing this operation at Atelier Casati Milano.

Yes, any strap with a 25-millimetre lug width is compatible. Milano Straps offers a specialised selection of 25mm straps in alligator, calf, NATO, and rubber. We recommend verifying that the strap has been tested for durability and that the deployante (if present) is made of noble material such as titanium or stainless steel, consistent with case quality.

A quality leather strap (alligator or vegetable-tanned calf) typically lasts 3–5 years with regular daily use, developing character patina over time. Durability depends on exposure to water, perspiration, and wear. A rubber or NATO strap resists longer under extreme conditions (sport, nautical), but does not acquire the aesthetic patina of natural leather.