ThePipingMart Blog other Flexible Coupling vs Spacer Coupling – What’s the Difference

Flexible Coupling vs Spacer Coupling – What’s the Difference

Flexible Coupling vs Spacer Coupling

Flexible couplings and spacer couplings are components used in various industrial applications. They join two rotating objects, such as motors and pumps, and transfer power from one to the other. Often, people need clarification on the two as they might look similar in design. But both of them come with different mechanisms that offer distinct advantages over each other. In this blog, we will provide a comprehensive comparison between flexible coupling and spacer coupling. So, let’s begin!

What is Flexible Coupling?

Flexible coupling is a mechanical device used to connect two rotating shafts in power transmission systems. It helps reduce vibration, noise, and shock caused by sudden high-speed changes while transmitting torque between the two shafts. Its flexibility allows for easy installation and maintenance as it permits axial movement, off-axis angular misalignment, and parallel misalignment of the two shafts. It also helps increase its life span by dampening torsional vibrations during operation. Flexible couplings include flanged, metallic disc or plate types, gear types, rubberized fabric or elastomeric couplings and universal joints.

What is Spacer Coupling?

Spacer coupling is an efficient method of transferring mechanical power, typically between two rotating shafts. It works with a spacer sleeve made from robust materials such as steel or aluminium alloy, securely fastened to both shafts. This allows the spacer to transmit torque from one shaft to the other while allowing for misalignment. Additionally, because of its design, it can accommodate angular, parallel and axial displacement while still functioning correctly – making it suitable for a wide range of applications where high torque needs to be transmitted over distances with varying degrees of motion. Spacer couplings are giving businesses an added level of reliability, accuracy and flexibility in their operations!

Difference Between Flexible Coupling and Spacer Coupling 

Working Concept

Flexible Coupling: A flexible coupling provides a mechanical connection between two rotating shafts while allowing them to move independently. It consists of two flanges connected by a flexible center using bolts or other temporary fastening devices. They absorb torsional vibration, compensate for shaft misalignments, and reduce noise transmission between the rotating components.

Spacer Coupling: A spacer coupling, on the other hand, is a device used to mechanically connect two rotating shafts by transmitting torque from one shaft to the other. They consist of two hubs connected by a spacer and fasteners that allow the movement of both shafts while maintaining an axial gap between them.

Misalignment Accommodation

Flexible Coupling: Flexible couplings are designed to accommodate misalignment between two shafts to ensure smooth operation. They offer angular, parallel, and axial misalignment compensation to some extent. They provide superior shock absorption and vibration damping, which helps reduce wear and tear of the driven components.

Spacer Coupling: Spacer couplings do not offer any misalignment compensation as rigid connections. They allow only axial movement and maintain a fixed distance between the shaft ends. They are primarily used where the shafts are already properly aligned or the driven component only requires a little torque.

Torque Capacity

Flexible Coupling: Flexible couplings can effectively transfer substantial torque with little to no backlash. They can withstand torsional loading and resist fatigue over a long period. They are ideal for high-power transmission, such as in the mining industry, printing press or machine tools.

Spacer Coupling: Spacer couplings have a limited torque transmitting capacity compared to their flexible counterparts. They are generally used where the shafts require little torque or rotational force.

Maintenance and Installation

Flexible Coupling: Proper installation and regular maintenance are necessary to prolong the life of a flexible coupling. It is a highly engineered component that tolerates minimal misalignment or improper installation. Regular lubrication and visual inspections can prevent wear and operating failure caused by ageing, corrosion, or overloading.

Spacer Coupling: Spacer coupling requires minimum maintenance, except for occasional lubrication of the sleeves’ mating surface to prevent wear and corrosion. They are comparatively easy to install. They require precision alignment and torque measurements to ensure proper installation, but they don’t require regular maintenance.


Both flexible coupling and spacer coupling are essential components in various industries that require power transmission and rotation movement. Each coupling mechanism type has advantages and disadvantages, and choosing the right one depends on the application’s needs and conditions. This blog post has provided enough information about the differences between flexible and spacer coupling to make a well-informed decision. Remember, always consult with a reliable coupling manufacturer and follow the best practices to ensure their proper installation, maintenance, and functioning.

Related Post