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Small transparent ball bearing block, single sheave, Ronstan Series 20

Ronstan

Ronstan Series 20 Bb Block Single boating maintenance

SKU CH-1EPD-DQJT2

A low-friction ball-bearing block with high static and dynamic load capacity for marine rigging

  • ColorTransparent
  • Low friction operation thanks to precision ball bearings
  • High static and dynamic load capacity for demanding lines
  • Lightweight Acetal sheave reduces overall rig weight
  • Series 20 compact block fits tight deck spaces
  • Single sheave design simplifies line handling

Ronstan Series 20 Single Block

This Ronstan Series 20 single block is a ball bearing component built for marine running rigging. It uses precision molded Acetal sheaves running on stainless steel or Torlon ball bearings to deliver low friction and high static and dynamic load capacity in a lightweight form.

Who This Suits and Who It Does Not

Sailors needing a compact, low friction single block for control lines or light sheets will find this model fits the purpose. Builders who require a double or triple block, a becket, or a higher load rating for primary sheets should look at other configurations.

Series 20 Ball Bearing Specification

The Series 20 designation defines the sheave and bearing size that matches specific line diameters and load requirements. Matching this specification to your rigging plan is the single factor that decides whether this block is the correct part.

Highlights

  • Low friction operation thanks to precision ball bearings
  • High static and dynamic load capacity for demanding lines
  • Lightweight Acetal sheave reduces overall rig weight
  • Series 20 compact block fits tight deck spaces
  • Single sheave design simplifies line handling

Specifications

ColorTransparent
BrandRONSTAN

Questions about this item

What line diameter fits the Series 20 block sheave?

The precision-moulded acetal sheave accepts lines suited to the Series 20 size for low-friction running.

How do you secure the RF20100 block to a deck or spar?

Fasten the single block through its central mounting point using marine-grade fasteners; the step often missed is bedding the base with sealant to stop water ingress.

When should the ball bearings be inspected or replaced?

Check the stainless steel or Torlon bearings each season for corrosion or flat spots; replace them if rotation feels gritty or play develops.

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