Ronstan, Series 55 Orbit Block™, Upright Lead, RF55171

Description

The Ronstan Series 55 Orbit Block™ is designed to be lightweight and efficient. With its unique orbital design, the bearing is positioned only in the active areas of the floating sheave, minimizing mass in the inactive return race and hub. This design reduces weight and bulk across different block configurations. The ball bearing single and becket block features a through-sheave becket arrangement, ensuring the lowest possible weight. Multi-sheave blocks have single intermediate cheeks and an ultra-light head arrangement, offering a 30% weight saving over competitors.

The block boasts the highest working load in its class, thanks to the orbital ball-bearing arrangement that maximizes load performance. The Ronstan 2-stage bearing system includes high compression grade acetal ball bearings and a secondary full-contact bearing, minimizing friction across the working load range. The floating sheave and bearing system are supported by a fiber-reinforced load frame, stress-optimized through computer modeling. The Dyneema® Link, made from FSE Robline SK75 fiber, is 10 times stronger and lighter than steel, providing a robust connection from the block.

Applications include mainsheet systems on dinghies, sportsboats, and small keelboats up to 9m, as well as halyard, vang, and backstay applications on boats up to 8m. It is also suitable for control line applications on larger yachts.

Specifications

• B.L. (kg): 1000
• M.W.L. (kg): 500
• Max. Rope diameter (mm): 10
• Sheave diameter (mm): 55
• Type of Block: Upright Lead
• Weight (g): 91