Grand Seiko
Spring Drive SBGA285— lug 20mm

The SBGA285 features a 20mm lug width, a standard dimension for Grand Seiko's 39mm cases. This size allows compatibility with most aftermarket straps, provided they are specifically manufactured for 20mm bars. To verify compatibility, measure the distance between the spring bar attachment points on your case; they must be exactly 20mm apart.

Alligator leather in vegetable tanning is the most refined choice for the champagne dial of the SBGA285, as the natural grain of the leather complements the sunburst effect of the dial. Alternatively, Hermès-grade calf or shell cordovan offer exceptional patina development over time. For sport-oriented wear, a raw cotton NATO or technical rubber strap highlights the versatility of the Spring Drive movement whilst maintaining connection to Japanese horological craftsmanship.

Remove the spring bars (small elastic pins) using a spring bar tool handled with care. Position the tool in the lateral groove of the spring, apply uniform downward pressure, and withdraw the pin. Reverse the procedure to install your new strap. Avoid hammers or screwdrivers, which risk damaging the lug lugs. If you lack tools or prefer assistance, the Casati Milano atelier can perform strap replacement whilst preserving the integrity of your case.

Yes, provided the strap is handcrafted and certified compatible with 20mm lug width. Heritage-quality aftermarket straps in alligator, shell cordovan, or calf leather do not damage the case and, conversely, allow personalisation of your timepiece according to your usage context. Milano Straps exclusively stocks straps manufactured to the same engineering tolerances demanded by luxury watchmakers, ensuring durable mechanical retention.

A quality alligator or calf leather strap evolves naturally over time, developing characteristic patina within 6–12 months of regular wear. Overall durability typically spans 2–4 years of daily use, depending on frequency of wear, sun exposure, and maintenance care. Vegetable-tanned leather ages superior to industrial tanning, acquiring chromatic depth. Casati Milano provides 18-month warranty on all bespoke straps, covering construction defects and guaranteeing technical support for eventual repairs.