Ronstan Series 20 Ball Bearing Block - Single - Cheek

The Ronstan Series 20 Ball Bearing Block – Single – Cheek is a precision-engineered rigging component designed for sailors, marine equipment manufacturers, and performance sailing applications requiring reliable line management. This single-sheave block excels in both cruising and racing environments where smooth, low-friction line movement directly impacts handling efficiency and crew safety. The cheek configuration makes it ideal for applications where space is limited or where a compact, streamlined profile enhances deck layout and reduces snag hazards.

Built with precision-molded Acetal sheaves rotating on stainless steel or Torlon bearing races, the Ronstan Series 20 Ball Bearing Block delivers exceptional low-friction performance under both static and dynamic loads. The double through-bolt mounting system distributes force across a wider footprint, maximizing load capacity and durability while minimizing stress concentration at fastening points. Weighing just 0.5 pounds and measuring a compact 2 x 1 x 3 inches, this block combines minimal weight penalty with substantial strength—critical for vessels where every ounce matters and where reliability during demanding conditions is non-negotiable.

This block is most beneficial for cruising sailboat owners upgrading control systems, racing teams optimizing sheet and control line setups, and marine riggers specifying components for custom or restoration projects. The cheek-style design integrates seamlessly into existing boom vang systems, mainsheet tackles, and jib sheet configurations where a single, load-rated block performs critical directional changes. Installation requires standard through-bolting to deck hardware or mast-mounted fittings; ensure fasteners and backing plates are properly sized for the anticipated load range to achieve maximum performance and safety margins.