Oris
Big Crown 01 754 7679 4331-07 8 20 32— lug 20mm

The lug width (or strap width) of the Oris Big Crown 01 754 7679 4331-07 8 20 32 is precisely 20 millimetres. This measurement represents the space between the lugs of the case where the strap anchors. To verify compatibility with an aftermarket strap, it is essential to measure from inside to inside of the lug fork with a digital calliper. A 20 mm strap inserts without forcing and permits minimal lateral movement, preserving case integrity. 19 mm straps remain mechanically locked; 21 mm straps slip dangerously during daily wear.

The ideal strap depends on primary use. For formal elegance and aeronautical contexts, cognac alligator with vegetable tanning is recommended, offering secure grip and accepting patina within 6–12 months without structural degradation. For urban versatility, calf leather dyed in absolute black or dark blue guarantees subtle grain and aesthetic coherence with the opaque dial. For aquatic activities and diving, FKM rubber (fluoroelastomer) remains the only option with superior grip in seawater and total chlorine tolerance. A NATO strap in cool grey or military beige converts the Big Crown into casual weekend reading without compromising functionality.

The strap is changed by extracting the spring bars that anchor the band to the case. With the watch facing upward and the dial visible, use a dedicated tool (spring bar remover) to compress the small retaining pin located laterally: the pin thereby retracts and the strap slides free. To install the new strap, align the lug with the lower lug fork of the case, insert the compressed pin, release gradually until the click of engagement. The operation requires delicacy to avoid scratching the case: professional ateliers offer this service with precision warranty.

Any strap with a 20 mm lug width is mechanically compatible with this Oris model. Artisanal straps in vegetable leather, alligator, shell cordovan or NATO ensure total compatibility if constructed to 20 mm specifications. It is essential to verify that the spring bars are of standard length (16 mm) and 1.8 mm diameter to guarantee stable fixing within the case lugs. Lower-quality straps with unstable pins may cause slipping during wear. Reliable brands, such as those offered by Milano Straps, certify construction tolerances and supply replacement pins in case of wear.

The lifespan of a vegetable-tanned leather strap depends on use and maintenance. With daily wear (5–7 days per week), a quality calf or alligator strap lasts 2–4 years before requiring material replacement: the leather thins, develops radial cracks, loses elasticity. Premium-thickness alligator resists 3–5 years. A NATO strap lasts 4–6 years with intensive use, since the resistant weave accepts surface wear without structural compromise. Patina—the controlled darkening and cracking that develops over time—does not indicate degradation but natural ageing that many collectors appreciate aesthetically. Monthly maintenance with natural mink oil significantly extends strap life and preserves material elasticity.