Black Zirconia Pulleys

Black Zirconia Pulleys for Roller Spearguns

The pair of Black Zirconia pulleys for Roller Speargun spearguns is built to ensure high reliability for spearfishing and freediving. The outer structure in black Delrin is machined from solid stock, ensuring dimensional precision and the strength required for underwater use.

Technical features

• Material: high-strength black Delrin, unaffected by corrosion and marine temperatures
• Maximum working load: 169 kg, significantly higher than equivalent 316 stainless steel bearings
• Rotation speed limit: 9000 rpm, more than three times higher than traditional stainless steel bearings
• Outside diameter: 28 mm
• Groove diameter (trapezoidal section): 20 mm, compatible with bands up to 16 mm in diameter
• Inner shaft bore diameter: 6 mm, intentionally larger to transfer the load to the bearing
• Thickness: 15 mm

Construction details and functional advantages

The pulley is equipped with a calibrated cap that allows the bearing to be precisely centered on the centerline, optimizing smooth rotation and reducing premature wear. The central bore, enlarged relative to the axle, shifts the working load primarily onto the bearing, improving mechanical efficiency and protecting the pulley from excessive stress.

The trapezoidal groove is designed to accommodate spearfishing bands up to 16 mm in diameter, ensuring proper grip without compromising the smoothness and responsiveness of the pulley during tracking and shaft release.

In addition, Black Zirconia pulleys require minimal maintenance, as they are highly resistant to the corrosive agents typical of the marine environment and to temperature variations, ensuring long-lasting use over time.