Strap for Space Chronograph 140 St

The Sinn 140.020 is fitted with 22mm lugs. This measurement is model-specific and critical for aftermarket strap compatibility. To verify compatibility, measure the internal space between the lugs at the widest point: it must correspond exactly to 22mm. Undersized straps will not insert correctly, whilst oversized straps will leave gaps and create irregular friction during rotation.

The ideal strap depends on intended use. For professional field applications, a black NATO fabric strap is the most authentic choice, lightweight and moisture-resistant. For civilian wear with occasional formal occasions, vegetable-tanned alligator develops a smoked patina that emphasises the chronograph's instrument-grade character. FKM rubber is the extreme solution for marine or aggressive climatic conditions. All materials must feature the correct 22mm lug width.

Strap change is performed via spring bars located at the lug ends. With the watch resting on the workbench, position a spring bar removal tool (or a blunt knife) beneath the spring from the internal side, applying gentle outward pressure until the spring retracts. Remove the old strap, align the lugs of the new accessory with the holes and insert them gently. The audible click of spring bar engagement must be clearly heard. Never force the bars: they are precision components and excessive pressure compromises their functionality.

Yes, the 140.020 fully accepts quality aftermarket straps provided they respect the 22mm lug width specification. Milano Straps offers a specialised range of 22mm straps in alligator, calf, NATO and rubber, all compatible. Transitioning to an aftermarket strap does not affect warranty or functionality, provided the lugs are not damaged during installation. Professional assistance is recommended for first-time strap changes.

The durability of a leather strap depends on frequency of use, ambient humidity and maintenance. Vegetable-tanned alligator worn daily on a 44mm chronograph (considerable mass) typically lasts 3–5 years before regeneration is required. Exposure to perspiration and salt water accelerates deterioration. Regenerated fabric NATO offers greater longevity in extreme conditions (8–10 years). FKM rubber resists indefinitely but degrades under UV radiation and ozone (5–7 years in dry climates). Proper drying after moisture exposure and protection from heat sources significantly extend strap lifespan.