Ronstan 45mm Core Stand-up Block - RF44140

Ronstan 45mm Core Stand-up Block - RF44140


Ronstan 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. 

Universal Bearing - Dynamic and high static load performance. The Ronstan Universal Bearing incorporates our proven 2-stage bearing system:
Stage 1 - Under moderate loads, Acetal ball bearings ensure minimum friction.
Stage 2 - Under heavy loads, where deformation of ball bearings alone would result in increased friction, a sliding Acetal bearing on a polished stainless steel race takes over, maintaining low friction performance.

Additionally the ball bearings are configured to act as a thrust bearing between the sheave and cheeks, preventing the sheave from rubbing on the cheeks and causing friction when the line lead in and out of the block isn’t perfect. Particularly important for cheek blocks.

Block cheeks are manufactured from the highest quality alloy for maximum strength. Material optimisation and the cut-away design minimises weight and allows easy fresh water rinsing of salt and debris from the bearings.


High dynamic and static load capacity
Efficient 2-stage bearing system
Ball bearings to counteract side thrust loads
Durable aluminium alloy cheek plates
Central hub can be used as a becket take-off or tie-up point, Max 11.5mm line
Features a strong cast padeye base with a swivel head post to allow full rotation and articulation


Ideal for mainsheet, halyard and spinnaker sheet applications on boats to 10m (33ft).
Various control line applications on larger yachts.
Alloy sheave models are available for use with wire.

Sheave Ø 45 mm
Max. Rope Ø 12 mm
M.W.L. 700 kg
B. L. 1400 kg
Weight 151 g