Omega
Speedmaster Broad Arrow 3657.20.31— lug 20mm

The lug width of the 3657.20.31 is 20.00mm, a non-standard measurement that requires targeted research. The width must be measured with millimeter precision in the inner lugs of the case, as even small variations can cause play or friction during wear.

Alligator leather (vegetable tanning) represents the most coherent choice with the elegance of white gold and the nature of the chronograph. For versatility, shell cordovan offers superior mechanical resistance and natural patina that evolves over time. For daily sportive wear, vegetable-tanned calf leather provides an excellent balance between aesthetics and practicality.

Strap replacement requires the use of appropriate tools (spring bar removers or thin-blade screwdrivers) to extract the pins from the lugs. Insert the pin into the new strap by correctly positioning the ring in its seat, ensuring that the lugs adhere perfectly to the case. For critical operations on chronographs, it is advisable to contact an authorized Omega service center.

Yes, you can use aftermarket straps compatible with the 20mm lug width, provided they are manufactured to precision standards. High-quality artisanal straps guarantee certified compatibility and allow customizations (leather, color, stitching thread) not available in the standard market.

Durability depends on the material: alligator and shell cordovan guarantee 3-5 years with daily use; simple calf leather 2-3 years. The frequency of strap changes affects the longevity of the product. With correct <a href="/pages/termine-glossario/concia-vegetale">vegetable tanning</a>, the leather develops natural patina rather than degrading, extending the period of conscious use.