RF28100 - Ronstan Series 25 Ball Bearing Block | Aztek Computers
29+Years
SKU: OXVT9XPX76 |  Mfg. Part: RF28100  | UPC: 9316800661916  | 
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RF28100 - Ronstan Series 25 Ball Bearing Block

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Condition: New

$30.86 
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Product Overview

Ronstan Series 25 Ball Bearing Orbit Block

The Series 25 Ball Bearing Orbit Block is a single sheave block designed for optimal performance in competitive sailing. Featuring a becket hub and swivel shackle head, it provides superior strength while being lightweight, making it ideal for high-demand applications on dinghies and small boats.

Engineered with Ronstan's high compression strength acetal bearing system, this block achieves an exceptional strength-to-weight ratio, ensuring it performs reliably under demanding conditions. Perfect for control line systems, such as mainsheets and spinnaker sheets, as well as cunninghams and cascading vangs for dinghies up to 4 meters.

Each block is fitted with a stainless steel hub compatible with 4mm (5/32") lashing for versatile setups, ensuring maximum efficiency in rigging and operation.

Expert Overview

The Ronstan Series 25 Ball Bearing Orbit Block (part number RF28100) is a single sheave block engineered for demanding marine applications. It is designed for use in competitive sailing environments, specifically on dinghies and small boats up to 4 meters. This block features a becket hub and a swivel shackle head, contributing to its strength while maintaining a lightweight profile. Its high compression strength acetal bearing system ensures reliable performance under stress. The Series 25 block is suitable for integration into control line systems, including mainsheets, spinnaker sheets, cunninghams, and cascading vangs. It supports lines up to 8mm (5/16") diameter and includes a stainless steel hub compatible with 4mm (5/32") lashing for flexible rigging configurations. This product addresses the need for durable, efficient, and lightweight bearing blocks in high-demand sailing setups.

Technical Specifications

  • 2-stage ball bearing system for smooth operation.
  • Compatible with lines up to 8mm (5/16”) diameter.
  • Hollow hub design enables becket take-off.
  • Accommodates lashing up to 4mm (5/32”).

Product Details

  • Manufacturer:
  • Model Number:
  • UPC:
  • Condition:
  • Weight:
  • Dimensions:
  • Updated:
  • Added:
  • Ronstan
  • RF28100
  • 9316800661916
  • New
  • 0.02 lbs
  • 5 X 1 X 2
  • Jul 23, 2026
  • Dec 30, 2025
Product Identifiers: Brand: Ronstan • Part #: RF28100 • UPC: 9316800661916 • Category: Bearing Blocks & Supports

Frequently Asked Questions

What types of lines are compatible with this block?

The Ronstan Series 25 Ball Bearing Block is compatible with lines up to 8mm (5/16") in diameter.

What is the maximum lashing size this block can accommodate?

This block is fitted with a stainless steel hub that can accommodate lashing up to 4mm (5/32").

What is the primary use case for this bearing block?

This block is designed for high-demand applications on dinghies and small boats up to 4 meters, suitable for control line systems such as mainsheets, spinnaker sheets, cunninghams, and cascading vangs.

Does this block feature a becket?

Yes, the Ronstan Series 25 Ball Bearing Block features a becket hub, and its hollow hub design enables becket take-off.

RF28100 - Ronstan Series 25 Ball Bearing Block

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$30.86