RONSTAN Series 40 Ball Bearing RF45101



  • Lightweight
  • Highest working load in its class
  • Secure, versatile attachment
  • Ultra low profile thru-sheave becket.
  • Low friction 2-stage ball bearing system provides consistent performance over the full working load range.
  • SP versions feature a Nylatron® sheave suitable for both rope and wire

27.51  VAT not included

Breaking load
Rodamientos de bolas
RF45101 PXA Polea simple, 40 8 325 700 33 27.51€
RF45110 PXC Polea simple, grillete giratorio, arraigo 40 8 325*1 650 44 30.39€
RF45111 PXB Polea simple, arraigo 40 8 325*1 700 36 30.39€
RF45131 PXC Polea simple, mordaza ajustable, arraigo 40 8 325*1 700 98
RF45201 PXE Polea doble 40 8 500 1000 67 57.61€
RF45211 PXF Polea doble, arraigo 40 8 500*2 1000 72 51.00€
RF45301 PXG Polea triple 40 8 650 1350 98
RF45311 PXH Polea triple, arraigo 40 8 650*3 1350 105
RF45151 PXD Polea plana de re-envío 40 8 325 700 32 25.51€
RF45501 PXI Polea violín* 40 + 22 8 325 700 47
RF45511 PXJ Polea violín,*, arraigo 40 + 22 8 325 700 48
RF45521 PXK Polea violín*, mordaza ajustable 40 + 22 8 325 700 108 83.27€
RF45531 PXL Polea violín*, arraigo, mordaza ajustable 40 + 22 8 325 700 109 86.98€
RF4 GWH Base giratoria con pasador. Apta para poleas de la Serie 40 & 55 provistos de gaza de Dyneema®. Pasador de 4.8 mm. 250 500 30
RF2454 PXU Base de fijación para poleas 325 700 11
* La roldana pequeña no dispone de un rodamiento de bolas. La roldana grande dispone de un rodamiento de bolas de dos etapas.


Kilogram for kilogram of working load, BB and RT Orbit Blocks™ 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 fibre-reinforced load frame. The design was computer modelled to be stress optimised.


Dyneema link specialties
To gain peak performance, we engineered out the heavy steel load straps, head post, shackle, full-length fasteners, and cleating accessories. Through extensive research and development, we replaced virtually all metal components with high-tech polymers and fibre equivalents.


The Dyneema Link is produced from FSE Robline SK75 fibre, which is 10 times stronger and lighter than steel, and provides the final connection from the block to the load point.

The flexible Dyneema Link provides controlled rotation and 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.

It is easily fitted and is retained securely by a moulded retainer clip. The flexible link can be left with one end attached to the block when fitting – no more lost shackle pins.

The system is compatible with Dyneema Spectra strops, webbing and carbon connection points – much more so than steel loop tops or shackles.


  • Mainsheet systems and spinnaker sheets on dinghies to 5m (16ft)
  • Spinnaker sheets on dinghies, sportsboats and small keel boats to 5m (16ft)
  • Halyard, vang and backstay applications on boats to 8m (26ft)
  • Control line applications on larger yachts


  • Ball Bearings – High compression stregnth carbon black Acetal
  • Stage 2 Bearing – Glass fibre reinforced, MoS2 impregnated Nylon
  • Frame/Cheeks – Toughened, glass fibre reinforced Nylon
  • Sheave – Carbon fibre reinforced, PTFE impregnated Nylon
Weight 1 kg
Dimensions 15 × 6 × 8 cm

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