Ronstan RF20302 Triple Ball Bearing Pulley 20mm – Series 20 Block

The Ronstan RF20302 Triple Ball Bearing Pulley (20mm) is a compact, high-performance Series 20 block designed for powerful purchase systems on modern sailing boats.

Featuring three precision 20mm acetal sheaves running on stainless steel ball bearings, this block delivers exceptionally low friction and smooth operation, even under load. It’s ideal for systems requiring efficient load distribution and fast adjustment.

Designed for versatility, the RF20302 includes a 2-axis shackle head that can be fixed at 0° or 90°, allowing optimal alignment with load direction to reduce friction and improve efficiency.

Built with UV-stabilised acetal sheaves, fibre-reinforced nylon cheeks, and 316 stainless steel load components, this block offers outstanding durability and resistance to corrosion in harsh marine environments.

With a maximum working load of 400kg and breaking load of 850kg, the RF20302 provides excellent strength in a lightweight, compact form—perfect for space-constrained, high-load applications.

Key Features

• Triple 20mm sheaves – high mechanical advantage for control systems
• Ball bearing system – ultra-low friction performance
• 2-axis shackle head – adjustable alignment (0° or 90°)
• High load capacity (400kg MWL / 850kg BL)
• Compact and lightweight (~62g)
• Durable composite construction – UV and corrosion resistant
• Low-profile design – ideal for tight rigging setups

Specifications

• Brand: Ronstan
• Model: RF20302
• Series: 20 Ball Bearing
• Product Type: Triple pulley block
• Sheave Diameter: 20mm
• Max Rope Diameter: 6mm
• Pin Diameter: 4.0mm
• Maximum Working Load: 400kg
• Breaking Load: 850kg
• Weight: ~62g
• Materials:
  • UV-stabilised acetal sheaves
  • Stainless steel ball bearings
  • 316 stainless steel load strap
  • Fibre-reinforced nylon cheeks

Ideal Applications

• Vang systems
• Cunningham and outhaul controls
• Traveller systems
• Dinghy and skiff rigging
• Multi-line control systems

This block is ideal where you need high mechanical advantage in a compact, lightweight setup without integrated cleating.

Why Buy from Barton Marine NZ?

• Trusted NZ Ronstan supplier
• Fast nationwide delivery
• Genuine high-performance sailing hardware
• Ideal for NZ racing and cruising conditions

Pro Tip  

• Use in cascading purchase systems for maximum efficiency
• Align the block using the 2-axis head to reduce friction
• Pair with low-stretch rope for optimal performance