Ronstan RF28109 Series 25 Orbit Ball Bearing Single Pulley

The Ronstan RF28109 Series 25 Orbit Ball Bearing Single Pulley is a lightweight, low-friction sailing block designed for high-performance dinghy, skiff, trailer sailer, and sports boat applications in demanding New Zealand sailing conditions. As part of Ronstan’s advanced Orbit Block™ range, the RF28109 delivers exceptional strength, smooth line handling, and minimal weight for efficient sail control and racing performance. Featuring a compact 25mm acetal sheave and Ronstan’s advanced 2-stage ball bearing system, the RF28109 provides extremely low-friction operation under both static and dynamic loads. The Orbit Block™ design uses fibre-reinforced nylon cheeks and a stainless steel load frame to achieve an excellent strength-to-weight ratio while maintaining reliable long-term marine durability. Ronstan specifically designed the Orbit range for “high dynamic and static load applications.” The RF28109 features a loop-top attachment system that allows lightweight soft attachment rigging without metal shackles, reducing weight and improving flexibility in modern racing systems. Its compact low-profile design makes it ideal for mainsheet systems, vang cascades, cunninghams, barber haulers, control lines, and spinnaker sheet turning systems where lightweight low-friction performance is critical. Suitable for ropes up to 8mm diameter, the Ronstan RF28109 is trusted by competitive sailors worldwide for dependable performance in high-load sailing control systems. Key Features Genuine Ronstan RF28109 Orbit Block 25mm single ball bearing pulley Lightweight loop-top attachment design Advanced 2-stage ball bearing system Extremely low-friction operation Fibre-reinforced nylon cheeks Stainless steel internal load frame Compact lightweight construction Ideal for dinghy and sports boat rigging Suitable for high dynamic loads Suits up to 8mm rope High-performance racing hardware Ronstan states the Orbit Block™ range provides: “Superior strength” “Reduced weight” “Exceptional performance” Why Buy the Ronstan RF28109 from Barton Marine NZ? At Barton Marine NZ we supply genuine Ronstan sailing hardware trusted by New Zealand sailors and racing enthusiasts. The RF28109 is an excellent low-friction pulley solution for modern lightweight rigging systems and high-performance sail control setups. Perfect for: Dinghy racing Sports boats Trailer sailers Mainsheet systems Vang cascades Cunningham controls Barber haulers Spinnaker systems Lightweight control lines High-performance sail trimming Technical Specifications Feature Specification Brand Ronstan Model RF28109 Product Type Single Ball Bearing Orbit Block Series 25 Orbit Sheave Diameter 25mm Maximum Rope Diameter 8mm Maximum Working Load 225kg Breaking Load 450kg Weight Approx. 13g Bearing System 2-Stage Ball Bearing Attachment Type Loop Top Ronstan specifications list: Max rope diameter: 8mm M.W.L: 225kg Breaking load: 450kg Weight: approximately 13g Common Applications The Ronstan RF28109 is commonly used for: Dinghy control systems Mainsheet turning blocks Spinnaker sheet controls Cascading vang systems Cunningham controls Lightweight rigging systems Sports boat sail controls High-performance trimming systems Barber haulers Racing yacht upgrades Ronstan recommends Series 25 Orbit Blocks™ for: “Control lines” “Mainsheet systems” “Cascading vangs” “High-performance dinghy applications” Performance Benefits The Ronstan RF28109 provides: Extremely smooth low-friction operation Lightweight racing performance Excellent strength-to-weight ratio Reliable high-load durability Efficient sail trimming control Reduced rigging weight Long-lasting marine reliability Loop-top Orbit Blocks™ are popular in racing applications because they reduce hardware weight while maintaining excellent load handling and flexibility.