Strap for Seamaster Bullhead 930

The Seamaster Bullhead ST 146.011 features a lug width of 20 millimeters, standard for sports chronographs from the 1960s and 1970s. This width is measured between the inner edges of the two upper lugs and ensures balanced proportions relative to the 41.50 millimeter case diameter.

For the Bullhead we recommend a black alligator strap for maximum aesthetic versatility, or a vegetable-tanned calf leather in cognac color to emphasize the vintage character. An FKM rubber strap remains the most authentic choice for sports and water use. The choice depends on your intended use and the aesthetic period you wish to emphasize.

To change the strap on the ST 146.011, use a spring bar removal tool. Position the tool in the small recess at the base of the lower lug, gently push inward to compress the spring, then remove the old strap. Repeat the operation on the other side. Inserting the new strap requires aligning the holes with the case lugs.

Yes, any strap with a 20 millimeter lug width is compatible with the ST 146.011. However, we recommend verifying that the strap thickness does not exceed 3.5-4 millimeters to ensure optimal fit through the case lugs without excessive play.

A high-quality artisanal leather strap, such as those made with vegetable tanning, has an estimated lifespan of 3-5 years with daily use. Longevity depends on frequency of use, climatic conditions, and maintenance: avoiding prolonged exposure to water and direct sunlight keeps the leather in optimal condition. An FKM rubber strap has a lifespan of 5-7 years before losing elasticity.