SKU: 48506214799

Ronstan Series 75 Core Block - Single [RF74100]

Sale price$138.47 Regular price$153.85
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Ships within 48 hours · Estimated delivery Aug 11 - Aug 16

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Description

Ronstan Series 75 Core Block - Single [RF74100]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

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 competitor
  • Universal head with full 3-axis articulation
  • Head posts can be locked at 0 or 90 degrees, by using a 2.5mm Hex/Allen Key
  • Central hub hole can be used as a becket take-off or tie-up point


Applications:
  • Ideal for mainsheet, halyard and spinnaker sheet applications on boats to 14M (46')
  • Various control line applications on larger yachts


Materials:
  • Sheave: U.V. stabilized Acetal
  • Cheek body: Aluminium Alloy
  • Ball Bearings: High compression strength carbon black Acetal
  • Shackle, head post & hub: Grade 316 stainless steel


Specifications:
Sheave Ø: 75mm(3")
Max. Rope Ø: 14mm(9/16")
Pin Ø: 8mm(5/16")
M.W.L.: 1,500kg(3,300lbs)
B. L.: 3,000kg(6,600lbs)
Weight: 354g(12.5oz)

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 48506214799

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Jocko
Lake Worth, US
★★★★★ 5
Very Comfortable Shoes
Size: 11, Color: Black Full Grain
Were purchased as a gift and the wearer says they are the most comfortable shoes he has
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 28, 2025
D
Verified Purchase
DALIA ALVAREZ
Natrona Heights, US
★★★★★ 5
Great shoes
I like these shoes they are comfortable, and look great. Good quality, it fits to its size.
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Reviewed in the United States on May 19, 2025
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Verified Purchase
Leonardo Perez
Los Angeles, US
★★★★★ 1
Mal presentado
Size: 9, Color: Black Full Grain
Un zapato llego con cosido defectuoso
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Reviewed in the United States on October 29, 2025
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Verified Purchase
Joe
Charlottesville, US
★★★★★ 5
Comfortable
Size: 11.5, Color: Black Full Grain
Fit great very comfortable
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Reviewed in the United States on October 16, 2025
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Verified Purchase
DAVID L.
Charlottesville, US
★★★★★ 5
Nice shoes!
Size: 11, Color: Black Full Grain
I bought them in black and I like them so much I will be buying the brown soon. They fit true to size and are comfortable and stylish. I like the clean simplicity. They're basically a dressy sneaker which is perfect for my job's 'dress code'. Yet they're stylish enough to be worn weekends or a night out. They seemed just a touch stiff out of the box but IMO that's completely normal and fine - after just a couple days of wearing them they are breaking in nicely. No complaints on that. They seem to be of very high quality and I'm very happy with them.
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Reviewed in the United States on February 8, 2026

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