Ronstan
Ronstan RF28100 Series 25 Orbit Ball Bearing Single Pulley
The Ronstan RF28100 Series 25 Orbit Ball Bearing Single Pulley is a lightweight, high-performance sailing block engineered for dinghies, skiffs, sports boats, and high-load control systems operating in demanding New Zealand sailing conditions. Designed as part of Ronstan’s renowned Orbit Block™ range, the RF28100 combines exceptional strength, ultra-low friction, and minimal weight to deliver reliable performance for competitive sailors and performance-oriented rigging systems.
Featuring a compact 25mm acetal ball bearing sheave with a swivel shackle head and integrated becket hub, the RF28100 provides smooth line handling and efficient load transfer in high-speed sail control applications. The advanced 2-stage ball bearing system minimises friction under both dynamic and static loads, improving trimming responsiveness and sail handling efficiency. Ronstan specifically designed the Series 25 Orbit range to achieve “the highest possible strength-to-weight ratio.”
The toughened glass fibre reinforced nylon cheeks provide excellent impact resistance and durability while keeping overall block weight extremely low. Its hollow hub design allows becket take-off functionality and versatile rigging configurations, making the RF28100 ideal for mainsheet systems, vang cascades, cunninghams, control lines, and spinnaker sheet turning blocks.
Suitable for dinghies up to 4 metres (13ft), the Ronstan RF28100 is trusted by racing sailors worldwide for smooth low-friction performance and long-term marine durability.
Key Features
- Genuine Ronstan RF28100 Orbit Block
- 25mm single ball bearing pulley block
- Swivel shackle head design
- Integrated becket hub
- Advanced 2-stage ball bearing system
- Lightweight high-strength construction
- Low-friction sail control performance
- Toughened glass fibre reinforced nylon cheeks
- Acetal ball bearing sheave
- Hollow hub for versatile rigging
- Suitable for up to 8mm rope
- Ideal for dinghy and sports boat sailing
Ronstan states the RF28100 features:
- “Superior strength”
- “Reduced weight”
- “Exceptional performance”
Why Buy the Ronstan RF28100 from Barton Marine NZ?
At Barton Marine NZ we supply genuine Ronstan sailing hardware trusted by New Zealand sailors, racers, and marine professionals. The RF28100 is an ideal low-friction pulley solution for high-performance dinghy rigging, sports boats, and sail control upgrades.
Perfect for:
- Dinghy racing
- Sports boats
- Skiffs and trailer sailers
- Mainsheet systems
- Vang cascades
- Cunningham systems
- Spinnaker sheet turning blocks
- Leech line controls
- Sail trimming systems
- Lightweight rigging upgrades
Technical Specifications
| Feature | Specification |
|---|---|
| Brand | Ronstan |
| Model | RF28100 |
| 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 | 18g |
| Bearing System | 2-Stage Ball Bearing |
| Head Type | Swivel Shackle |
| Becket | Yes |
Ronstan specifications list:
- Maximum rope diameter: 8mm
- M.W.L: 225kg
- Breaking load: 450kg
- Weight: 18g
Common Applications
The Ronstan RF28100 is commonly used for:
- Mainsheet turning blocks
- Spinnaker sheet systems
- Cunningham controls
- Cascading vang systems
- Dinghy sail controls
- Sports boat rigging
- Lightweight sail handling systems
- Leech line controls
- Racing yacht upgrades
- High-performance trimming systems
Ronstan recommends the RF28100 for:
- “Mainsheet and spinnaker sheet turning blocks”
- “Control lines”
- “Cascading vangs”
- “Leech lines & cunninghams”
Performance Benefits
The Ronstan RF28100 provides:
- Extremely low-friction operation
- Lightweight racing performance
- Smooth line handling under load
- Excellent strength-to-weight ratio
- Reliable high-load durability
- Improved sail trimming precision
- Long-lasting marine reliability
Ronstan’s Orbit Block™ systems are engineered for “high-demand dinghy and small boat applications.”
