Click to enlargeRonstan Series 75 Core Block™ - Single
Manufacturer: RonstanPart #: RF74100SKU: 55264
- Stainless Steel
Item #: 55264
Category: Blocks
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Description
Series 75 Core Block™ - Single 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.
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.
Alloy Cheek Plates 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.
Cheek design has been further styled with flaring at the block throat and reduced gap between the cheek and sheave, minimising rope wear. Universal head The head assembly incorporates a brass bearing washer to provide smooth 360™ rotation of the post and shackle.
A set screw arrangement allows the head to be locked at 0™ or 90™. Shackles are high quality forged grade 316 stainless steel.
Features: Class leading performance and sleek, contemporary styling Excellent dynamic and high static load performance Less than half the friction of the nearest c
Specifications
| Brand | Ronstan |
|---|---|
| Part Number | RF74100 |
| EverTide SKU | 55264 |
| UPC | 9316800413225 |
| Material | Stainless Steel |
Specifications are provided by the manufacturer. Confirm fitment for your application before ordering, or contact us and we'll help.
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Returns & warranty
Returns are accepted within 30 dayson items that are unused and in their original packaging. Some items may be subject to a manufacturer restocking fee. Special-order items may not be eligible — if you're unsure, ask us before ordering.
Ronstan productscarry the manufacturer's standard warranty. For a warranty claim or a return authorization, see our full returns policy or contact us.
Sailing — frequently asked
- How do I size a block for my sailboat?
- Match the block to the line diameter it will carry and to the working and breaking loads of the system (sheet, halyard, control line). Makers publish load ratings and line-size ranges — choose a block whose working load comfortably exceeds the real-world load, without going so large it adds needless weight.
- What is running rigging?
- Running rigging is the moving lines that control the sails — sheets, halyards, and control lines — as opposed to standing rigging (the fixed wire that holds up the mast). Running rigging should be matched to the boat’s blocks, clutches, and winches for smooth, reliable sail handling.
- How do I maintain sailboat winches and hardware?
- Rinse with fresh water after sailing, keep sheaves and bearings clean, and periodically service winches (disassemble, clean, and re-grease per the maker’s instructions). Marine-grade stainless and good maintenance keep hardware working smoothly when loads are high and timing matters.
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