Ronstan Series 40 Ball Bearing Orbit Block™ – Single – Becket – Swivel Head

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Manufacturer: Ronstan
Part Number: RF45110
UPC: 9316800440429
SKU: 55218
MSRP: $35.95 --- Discount 37%
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Ronstan Series 40 Ball Bearing Orbit Block™ - Single - Becket - Swivel Head

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Series 40 Ball Bearing Orbit Block™ – Single – Becket – Swivel Head

Core Blocks™ are a true all round solution. A tuned 2-stage bearing system provides excellent performance across the full working load range with an integrated thrust bearing feature and the resilience to handle high dynamic or static loads. Acetal sheave, alloy cheeks and stainless fixings complete the durable package. For reliability and a long service life, these blocks are the right choice for sheets, halyards and control line applications for cruising and racing.

Kilogram for kilogram of working load, BB Orbit Blocks&#153 are the world’s lightest. The unique orbital design allows the bearing to only be in the active areas of the floating sheave. This minimises the mass of the inactive return race and hub.

Weight and bulk are further reduced in the different block configurations. The ball bearing single and becket block has a through-sheave becket arrangement. The result? The lowest weight possible.

Multi-sheave blocks have only single intermediate cheeks and an ultra-light and efficient head arrangement. This gives a 30% weight saving advantage over the nearest competitor. Other brands just link together their single blocks. This results in unnecessary double cheeks between each sheave, held together by a heavy steel channel across the top of the block.

Highest Working Load In Its Class
The orbital ball-bearing arrangement gives the largest possible bearing race diameter. This maximises load performance. The proven Ronstan 2-stage bearing system features high compression grade acetal ball bearings and a secondary full-contact bearing. This gives minimum friction across the full working load range.

The floating sheave and bearing system is supported by a fiber-reinforced load frame. The design was computer modelled to be stress optimised.


  • Ultra Lightweight
  • Low friction 2-stage Orbital ball bearing system
  • Highest working load in its class
  • Low profile and compact
  • High performance cleating
  • Swivel shackle head for unlimited block rotation
  • Stainless steel shackle head for ultimate durability and compatibility with harsh fixing points
  • Ultra low profile integrated becket


  • Spinnaker sheets on dinghies, sportsboats and small keel boats to 5M(16′)
  • Halyard, vang and backstay applications on boats to 8M(26′)
  • Control line applications on larger yachts


  • Ball Bearings – High compression stregnth carbon black Acetal
  • Stage 2 Bearing – Glass fiber reinforced, MoS2 impregnated Nylon
  • Frame/Cheeks – Toughened, glass fiber reinforced Nylon
  • Sheave – Carbon fiber reinforced, PTFE impreganated Nylon
  • Head fitting: Grade 316 stainless steel

Sheave Ø: 40mm(1-9/16″)
M.W.L.: 325kg(715lbs)
B. L.: 650kg(1,430lbs)
Weight: 44g(1.6oz)

SKU: 55218 Categories: ,



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