Nivada Grenchen
Super Antarctic 35013M40— lug 18mm

The lug width of the Nivada Grenchen Super Antarctic 35013M40 is 18 millimetres. This measurement, taken from the distance between the spring bars that connect the case to the strap, represents the original Swiss design specification and ensures complete compatibility with aftermarket straps of matching dimensions. You can verify this using a digital calliper or by consulting the original product documentation.

For the 35013M40, we recommend three primary options: 1) Alligator with vegetable tanning in brown or cognac, for a formal, vintage appearance faithful to the original era; 2) Calf leather in honey or grey tortoiseshell tones, for a contemporary aesthetic balanced with elegance; 3) NATO in Cordura fabric, for historical authenticity and practicality in active environments. Your choice depends on primary use: formal/professional, versatile daily wear, or exploratory/outdoor activities.

Changing the strap on a 35013M40 requires: 1) A spring bar tool (with bifid end); 2) A stable, well-lit work surface; 3) Procedure: insert the flat end of the spring bar tool beneath the outer spring bar, compress the internal spring and slide the bar from its seat; 4) Repeat for the second bar; 5) Insert both bars into the new 18mm strap, verifying that the ends click firmly into their sockets. No excessive force is needed—the motion must be smooth and precise.

Any standard strap with an 18-millimetre lug width is compatible with the 35013M40. This includes: alligator, calf, shell cordovan, suede, NATO canvas, vulcanised rubber, and even steel mesh straps. The essential requirement is that the strap features removable 18mm bars. Avoid fixed-lug straps or those with different widths, as these would require case modification.

The durability of a premium leather strap depends on usage intensity, tanning method, and environmental conditions. An alligator or calf strap with vegetable tanning, used daily, typically lasts 3–5 years before replacement is necessary. The patina that develops on the surface over time is natural and desirable, adding character. If exposed to abundant perspiration, persistent humidity, or direct UV radiation, lifespan may reduce to 2–3 years. To maximise longevity, allow the strap to rest 1–2 days between extended wears, avoid prolonged water immersion, and periodically apply a protective balm formulated for leather.