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Ships within 48 hours · Estimated delivery Jul 26 - Jul 31
For Your Every Summer RSVP, with Code: SUMMER15
Description
Ronstan Series 45 Core Block - Single - Swivel Shackle HeadSeries 45 Core Block Single Swivel Shackle Head 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,
Series 45 Core Block - Single - Swivel Shackle HeadCore 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.
Features:
- High dynamic and static load capacity
- Efficient 2-stage bearing system
- Ball bearings to counteract side thrust loads
- Class leading performance and sleek, contemporary styling
- Durable aluminium alloy cheek plates
- 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 10M (33')
- Various control line applications on larger yachts
- Alloy sheave models are available for use with wire
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: 45mm(1-3/4")
Max. Rope Ø: 12mm(1/2")
Pin Ø: 5mm(3/16")
M.W.L.: 700kg(1,540lbs)
B. L.: 1,400kg(3,090lbs)
Weight: 104g(3.6oz)
Manufacturer : Ronstan
Manufacturer Part No : RF44100
UPC : 9316800466153
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- 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
4.4 ★★★★★
Based on 14 reviews
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Product Reviews
★★★★★ 5
Great Quality
Great quality and fit as expected.
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Reviewed in the United States on May 17, 2025
★★★★★ 5
Buy small and not big
The product was definitely an awesome product I wore the pants one time realize that I got a Size 52 I should have got a size 50 they are a little too big on me. I probably pass them on to a friend that's a little bit bigger than me and I need to lose 100 lb so and then all my other jeans will fit me but I will not have a problem buying any type of jeans from this company. I really enjoyed the product and I know I'll be buying smaller sizes in the future
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Reviewed in the United States on August 14, 2017
★★★★★ 5
Big mans stretch jeans
Fit Type: Relaxed, Color: Black, Size: 64W x 28L
Son is in the nursing home and wheel chair bound. Wants to feel normal and these will help
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Reviewed in the United States on October 25, 2025
★★★★★ 1
retruns not free despite being labelled as such.
waist fine. length...rediculously long, thigh and calf stupidly narrow for larger sizes. also, despit it claiming that it offers free returns, they evidently charge something like $4? i dont know yet as they dont say exactly how much, but rather that it will be deducted from the refund. very deceptive.
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Reviewed in the United States on December 29, 2022
★★★★★ 4
Everything was as expected
Fit Type: Relaxed, Color: Antique Indigo, Size: 52W x 28L
Product quality was good and delivered as expected. Very satisfied.
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Reviewed in the United States on July 3, 2020