Blocks Selection Advice

Available as sheaves only, or in Single, double, and triple pulley arrangements, Ronstan’s range of pulleys cover a full range of rope diameters and load capacities and can be supplied for use with wire or fibre rope. When looking to incorporate blocks into your design, there are a few points that are helpful to consider.

PHOTO CREDIT:© Ronstan International Pty Ltd
Required Load capacity and Factor of Safety

Ronstan blocks are classified by either Max Working Load (MWL) or Breaking Load (BL). In addition, it is important to consider the variations in loads and operating conditions that the component might be exposed to and ensure that an appropriate factor of safety is used. More information on these terms can be found at (Link)

Rope type and diameter

Some blocks are only suitable for fibre ropes. Others can be provided with sheaves that are suitable for wire rope. These are made from Aluminium and use a different groove shape to help retain the rope.

Rope speed and operational frequency

Applications with higher rope speed or higher frequency operation may require a higher performance bearing system to minimize the amount of heat generated, or accommodate the heat that is generated.

Attachment point details

What the block is being fixed to and the alignment of the fixing points with the direction of the load will both influence block selection. However, Ronstan blocks are available with a wide range of mounting details, and if you do not see what you need, we may be able to manufacture something to suit.

Purchase system

When blocks are grouped together, they can be used to magnify the load applied to the mounting points. Ronstan have a range of standard purchase systems or can provide pairs of blocks which combine to form the basis of a purchase system.

 All Purpose Blocks

All Purpose Utility Blocks

Ronstan All Purpose Utility Blocks are a great choice for durability and a long service life. They feature self-lubricating acetal polymer sheaves running on polished stainless-steel races and perform equally well with dynamic loads and static loads.

Ball Bearing Blocks

Ball Bearing Utility Blocks

Ronstan's Ball Bearing Utility blocks have a similar look to the All-purpose utility blocks but feature a 2-stage bearing system to achieve the best combination of working friction and capacity over a range of loads. Under moderate loads, acetal ball bearings ensure minimum friction.

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.

Ball Bearing Blocks

Special Purpose Utility Blocks

Ultimate High & Static Load Performance

Special Purpose Utility Blocks are based upon the same design concept as the Ronstan high performance Ball Bearing blocks, but utilise a full contact bearing for ultimate performance in high load or prolonged static load applications.

Orbit Block Ball Bearing

Ball Bearing
Orbit Blocks™


Ball bearing orbit blocks feature side plates manufactured from high-tech polymers to make them lightweight and corrosion proof. They feature a 2-stage bearing system to provide the best combination of rolling friction and load capacity over a broad range of loads and rotational speeds.

Core Blocks

Core Blocks™

A balanced design approach incorporating functionality, performance and style makes our Core Blocks™ a great option for moderate to high loads.

All core blocks feature a tuned 2-stage bearing system providing excellent performance across the full working load range with an integrated thrust bearing feature and the resilience to handle high dynamic or static loads. Side plates are manufactured from aluminium alloy, providing high strength, lightweight, and corrosion resistance. The swivelling head post with integrated shackle is fitted with a brass bearing washer providing smoother rotation helping to achieve correct alignment.

Aluminium sheaves are available to allow use with wire rope.

2-stage bearing
2-stage bearing
Universal Head
Universal Head
Aluminium Alloy Cheek Plates
Aluminium Alloy Cheek Plates
Orbit Blocks™

Orbit Blocks™


Orbit Blocks™ are a no-compromise product range developed to achieve the highest load capacity with minimum possible rolling friction across the load range. The Orbit sheave has captive Acetal or Torlon® ball bearings for side thrust loads, eliminating the need for side retainer plates. This reduces weight and allows for a wider bearing surface that can accommodate longer Torlon® needles - achieving a substantially higher strength-to-weight ratio.

Soft Attachment Blocks

Soft Attachment Blocks

Designed from the outset to deliver outstanding performance, these blocks achieve the highest ratings for dynamic load vs sheave diameter. They are built to perform and built to last. Every SA Block features fully machined, anodised aluminium cheek plates. Sheaves run on duplex stainless-steel hubs and incorporate precision composite journal bearings and thrust washers. The soft attachment is a purpose designed Dyneema® SK99 cord shackle with titanium dog bone. It reduces the risk of damage to mating surfaces and allows the block to align with the applied load.

Rope is installed or removed onto the sheave by releasing the cord shackle, and then rotating the two halves of the block.

Soft Attachment Blocks

Snatch Blocks

Snatch blocks are a tough and reliable solution when a removable arrangement is required, or where the rope needs to be frequently installed or removed from the pulley. Simple and quick to deploy, they can be easily opened when the load is released, to allow rope access. The standard snap shackle head allows the block to swivel through 360°, and also provides quick attachment / release to a mounting point. Soft resilient cheeks reduce clatter and surrounding surfaces from damage.

Upright & Pivoting Low Lead Blocks

Upright & Pivoting Low Lead Blocks

These blocks are designed to provide a diversion point for ropes running parallel to a surface. For fixed upright blocks, the rope is diverted perpendicular to the surface. With pivoting lead blocks, the body is mounted on a pair of pivots, allowing it to swing through an arc of almost 180 degrees. The pivot points are hollow, allowing the rope to pass through them and then be diverted onto the sheave.

All blocks can be disassembled for assembly and servicing.

View Upright & Pivoting Low Lead Blocks
Purchase System

Purchase Systems

Purchase systems, also known and block and tackle systems, thread the rope through multiple sheaves to magnify the load applied at the sheave attachment points.

Ronstan manufacture finished purchase systems in several different diameter and rope length configurations. In addition, we have a wide range of components we can draw from to provide a system which perfectly meets your needs.

View Purchase Systems