Ronstan Series 30 Ball Bearing, Orbit Block

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Product Description

Ball Bearing Orbit Blocks™ boast the highest strength-to-weight ratio available.  This is achieved through all-composite reinforced polymer materials and multiple attachment options.


Their precision design provides the optimum number of ball bearings for minimum friction while weight reduction is achieved through the use of fibre-reinforced composites in the block head, cleat arms and beckets.


Kilogram for kilogram of working load BB Orbit Blocks™ are the world’s lightest. To gain peak performance, we engineered out the heavy steel load straps, head post, shackle and cleating accessories. Through extensive research and development, we replaced virtually all metal components with high-tech polymers and fibre equivalents.

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. Other brands just link together their single blocks with a heavy steel channel across the top of the block, with unnecessary extra cheeks adding extra weight and bulk not found in Ronstan Orbit Blocks™.

Highest working load in its class

The proven Ronstan 2-stage bearing system (Series 30 and larger) features high compression grade Acetal ball bearings and a secondary full-contact bearing. This gives minimum friction across the full working load range. 

The sheave and bearing system is supported by a fibre-reinforced load frame, computer modelled and optimised using advanced stress analysis methods. The Dyneema® Link, used in multi-sheave blocks, is produced from high spec SK75 fibre, which is 10 times stronger and lighter than steel, and provides the final connection from the block to the load point.

Simple, versatile and secure attachment

The single block is easily lashed to an attachment point, and can also accept Dyneema® Links and shackles for a variety of efficient attachment alternatives. The Dyneema® Link used in multi-sheave blocks is easily fitted and secured by a removable pin.  The Dyneema® Link can also be removed and replaced by a shackle, custom lashing or strop.

These blocks are far more compatible with Dyneema®/Spectra® lines, carbon laminate connection points and webbing than traditional blocks with steel loop tops or shackles.

Low profile and compact

The two way head in the single lashing block allows for alignment at 0° or 90° orientation, while the single swivel block allows for full articulation.

The flexible Dyneema® Link used in multi-sheave blocks provides 0° or 90° orientation. It connects directly to the head of the block rather than to an intermediate head post. This reduces weight and gives the lowest possible profile while allowing full articulation. 

Beckets have been carefully designed to minimise height. 

High performance cleating

Ronstan BB Orbit Blocks™ feature strong, lightweight fibre-reinforced cleat arms optimised at the required cleating angle. Race-proven, carbon-fibre reinforced Ronstan C-Cleats give secure rope holding with low entry and exit efforts, and are fitted with fairleads for fast action from any angle.

*RF35100 & RF35100D have stainless steel head posts & shackles.

*RF35141: Recommended fasteners - 2 x 5mm (3/16") countersunk head screws

*RF35202: Low friction 2-stage ball bearing system provides consistent performance over the full working load range


- Lightweight

- Highest working load in its class

- Secure, versatile and secure attachement

- Low profile and compact


- Mainsheet systems and spinnaker sheets on dinghies to 5m (16ft)

- Halyard, vang and backstay applications on boats to 5m (16ft)

- Control line applications on larger yachts


- Sheave: High compression strength carbon black Acetal

- Ball Bearings: High compression strength Acetal

- Frame/Cheeks: Toughened, glass fibre reinforced Nylon

- Link: UV stabilised, multi-strand impregnated SK75 Dyneema®

RF35141 Specifications:

Sheave Ø: 30mm

Max. Rope Ø: 8mm

Max. Cable Ø: - mm

Pin Ø: - mm

M.W.L.: 300kg

B. L.: 600kg

Weight: 36g

RF35100 Specifications:

Sheave Ø: 30mm

Max. Rope Ø: 8mm

Max. Cable Ø: - mm

Pin Ø: 4mm

M.W.L.: 300kg

B. L.: 600kg

Weight: 32g

RF35202 Specifications:

Sheave Ø: 30mm

Max. Rope Ø: 8mm

Max. Cable Ø: - mm

Pin Ø: - mm

M.W.L.: 450kg

B. L.: 900kg

Weight: 56g

SKU: #

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