SKU: 52222429116

Ronstan Series 55 Ball Bearing Orbit Block - Single - Becket - Swivel Head [RF55110]

Sale price$45.52 Regular price$50.58
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Description

Ronstan Series 55 Ball Bearing Orbit Block - Single - Becket - Swivel Head [RF55110]Series 55 Ball Bearing Orbit Block Single Becket Swivel Head Lightweight 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

Series 55 Ball Bearing Orbit Block™ - Single - Becket - Swivel Head

Lightweight
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 fiber-reinforced load frame. The design was computer modelled to be stress optimised. The Dyneema® Link is produced from FSE Robline SK75 fiber, which is 10 times stronger and lighter than steel, and provides the final connection from the block to the load point.

Features:

  • Ultra Lightweight
  • Low friction 2-stage Orbital ball bearing system
  • Highest working load in its class
  • Low profile and compact
  • High performance cleating
  • Swivel shackle head for unlimited block rotation
  • Stainless steel shackle head for ultimate durability and compatibility with harsh fixing points
  • Ultra low profile integrated becket


Applications:
  • Mainsheet systems on dinghies, sportsboats and small keelboats to 9M(30')
  • Spinnaker sheets on dinghies, sportsboats and small keel boats to 9M(30')
  • Halyard, Vang and Backstay application on boats to 8M(26')
  • Control line applications on larger yachts
  • Ideal use for mainsheet systems and spinnaker sheets on dinghies, sportsboats and small keel boats to 9M(30')
  • Also ideal with halyard, vang and backstay applications on boats to 8M(26')
  • Spinnaker sheets on sportsboats and small keel boats (lateral lead blocks)
  • Control line applications on larger yachts


Materials:
  • Ball bearings - High compression strength carbon black Acetal
  • Stage 2 bearing - Carbon fiber reinforced, PTFE impregnated Nylon
  • Frame/Cheeks - Toughened, glass fiber reinforced Nylon
  • Rope Link: UV stabilized, multi-strand impregmented SK75 Dyneema®
  • Sheave: Carbon fiber reinforced, PTFE impregnated Nylon
  • Head fitting: Grade 316 stainless steel.


Specifications:
Sheave Ø: 55mm(2-5/32")
Max. Rope Ø: 10mm(3/8")
M.W.L.: 500kg(1,100lbs)
B. L.: 1,000kg(2,200lbs)
Weight: 88g(3.1oz)
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: 52222429116

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David Williams
Los Angeles, US
★★★★★ 5
Use as directed, when needed, and you'll be good to go.
A must have if you have a need for a ZDDP additive. This won't fix your worn valve seats, leaking piston rings, seasonal depression or gout but it will improve the lubricating properties of a quality oil in a properly maintained motor for your longevity goals.
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Reviewed in the United States on February 5, 2026
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Michael R.
Lowell, US
★★★★★ 5
Every oil change for bikes
I use this in my bike every oil change
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Reviewed in the United States on April 8, 2026
L
Verified Purchase
Larry Musgrave
Belleville, US
★★★★★ 5
Buddy filled diesel skid steer with automotive gas engine oil. Used this to help.
We all know that guy who will buy a $65,000 machine and then only service it once a year with the cheapest oil on the shelf from Rural King or some other place with ultra cheap, home branded, questionably quality oil. Yep. That is my good buddy. So I go to the shop a couple weeks back and he is re-filling the skid steer engine with some ultra cheap, totally not to spec, gas engine oil. I question him and he states that it is perfect oil for the machine being 5W-30. I ask him if it meets the SAE ratings for the diesel, he repeats back that yep... it is 5W-30. So I go grab his New Holland book (C232 track skid steer) and look up the oil requirements, then I look at this junk oil, and I try to explain to him the SAE designations on the back of the bottle and the SAE requirements in the book. He looks at me like I have 3 heads and repeats that it is 5W-30, it is totally good. Someone.... kill me please! He has no clue what I am trying to explain. So I couldn't sleep knowing what he is doing, and I ran to Amazon to see if I can at least get zinc to add to the wrong oil and try to help the cam followers and rockers survive this next year. I found this. I ordered a few bottles and had them shipped to his shop, and I explained to him that these need to be dumped in to at least make an attempt in not prematurely wear the engine that likely is worth $20,000 or more! So the real question is, will he actually dump these into the machine, or will he toss them on a shelf never to be seen again? We may never know. But I bet next winter he will once again shop for the cheapest oil on earth to put in a machine that costs as much as some peoples home. He is who he is, you can never change that.
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Reviewed in the United States on February 6, 2023
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Verified Purchase
J. Bee
Chelsea, US
★★★★★ 5
Works good for my old tractor
Put it in my old 1953 Ford Golden Jubilee
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Reviewed in the United States on September 28, 2025
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LovesAmazon24
Omaha, US
★★★★★ 5
High quality replacement clips. Highly recommend.
I used these when replacing the headlight assemblies on my 2011 Honda CR-V. A few clips were already missing before I even started taking the bumper off, and of course a couple more didn’t survive the job. These fit perfectly and snapped right in with no issues. If you’re missing clips or break some while doing a repair, these are a simple fix that gets everything secured again. Very good deal.
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Reviewed in the United States on March 8, 2026

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