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KTR BoWex Elastic

KTR BoWex-ELASTIC Couplings: Identification, Sizes and Technical Guides

Explore practical KTR BoWex-ELASTIC coupling guides for engineers, maintenance teams, equipment owners and spare-parts buyers. This technical knowledge section explains how to identify an installed BoWex-ELASTIC coupling element, interpret its description, determine the correct size, check the HE execution and confirm the required Shore hardness.

BoWex-ELASTIC is a highly flexible flange coupling system used in demanding engine-driven applications. The coupling combines an elastic ring-shaped element with an axially inserted BoWex hub. Correct replacement selection requires more than matching the general shape or outside diameter.

The articles in this category focus on practical identification, inspection and replacement questions. Use them to collect the correct technical information before ordering and to avoid selecting an element with the wrong size, mounting execution, SAE connection or elastomer hardness.

What Is a KTR BoWex-ELASTIC Coupling?

KTR BoWex-ELASTIC is a highly flexible flange coupling designed to transfer torque while damping torsional vibration, reducing shock loads and limiting structure-borne noise.

The coupling normally consists of:

• A circular, highly flexible elastomer element
• An engine-side flange connection
• An internally toothed connection within the element
• An axially inserted BoWex hub with external curved teeth
• The required fastening and mounting components

The plug-in construction allows the internal BoWex hub to engage axially with the elastic element. The complete assembly can accommodate drivetrain displacement within the limits specified for the selected coupling type.

BoWex-ELASTIC couplings are available in different sizes, elastomer hardnesses, HE designs and engine-side flange dimensions. These variants should not be treated as interchangeable simply because their general construction appears similar.

How to Identify a KTR BoWex Elastic Coupling

Correct identification should begin with the complete description visible on the installed elastic element. Inspect the front, rear and complete circumference because dirt, paint, oil or the mounting position can conceal part of the marking.

Use the KTR BoWex Elastic identification guide to understand which markings, dimensions and photographs should be collected.

Look for information such as:

• KTR or KTR-Kupplungstechnik manufacturer identification
• BoWex-ELASTIC product family name
• The nominal element size
• The HE, HE1, HE2, HE3 or HE4 designation
• The engine-side flange or SAE size
• The outside flange diameter
• The T40, T50 or T65 Shore A hardness
• Production, drawing or traceability numbers

Copy the complete description exactly as it appears. Do not omit letters, numbers, fractions or the Shore hardness because each part can be relevant to identifying the correct replacement.

Understanding a BoWex-ELASTIC Product Description

A typical element description may appear in a format similar to:

BoWex-ELASTIC 48 HE 6 1/2

The individual sections provide different identification information:

• BoWex-ELASTIC identifies the KTR coupling family
• 48 identifies the nominal element size
• HE indicates the highly elastic coupling execution
• 6 1/2 can identify the engine-side SAE flange connection

More detailed product descriptions may also specify the HE1/HE2 or HE3/HE4 execution, actual flange diameter and Shore hardness.

For example, a listing such as BoWex Elastic 48 HE1/HE2 Ø215.8 SAE6.5 Shore 50 contains significantly more selection information than the general description “BoWex Elastic 48”.

Information Required Before Ordering

Before requesting a replacement BoWex-ELASTIC element, collect all available information from the existing coupling and the complete machine.

Please provide:

• The complete description visible on the element
• The nominal BoWex-ELASTIC size
• The HE1, HE2, HE3 or HE4 execution
• The original T40, T50 or T65 Shore A hardness
• The outside flange diameter
• The SAE flywheel designation, where applicable
• The number of internal teeth
• The internal toothed opening diameter
• The element width and other principal dimensions
• The matching BoWex hub marking
• The hub bore, spline or shaft dimensions
• The engine manufacturer and model
• The generator, compressor, pump or gearbox model
• The machine manufacturer, model and serial number
• Clear photographs of both sides of the element
• A photograph of the complete installed coupling assembly

The full product description should be used as the primary identification reference whenever it remains readable. Dimensions, photographs and machine information should provide additional confirmation.

KTR BoWex Elastic Coupling Sizes

The current AWELASTIC range includes original BoWex-ELASTIC elements in five principal nominal sizes:

• KTR BoWex Elastic 42
• KTR BoWex Elastic 48
• KTR BoWex Elastic 65
• KTR BoWex Elastic 80
• KTR BoWex Elastic 100

The nominal size is only one part of the selection. Elements within the same size can differ by HE execution, outside diameter, SAE connection and Shore hardness.

KTR BoWex Elastic 42

BoWex-ELASTIC 42 is used in relatively compact engine-driven applications. The AWELASTIC range includes HE1/HE2 elements with different flange dimensions and Shore hardness options.

When identifying a size 42 element, verify:

• The complete 42 HE description
• The HE1 or HE2 execution
• The outside flange diameter
• Whether an SAE 6.5 connection is specified
• The original Shore hardness
• The matching internal toothed hub

A BoWex-ELASTIC 42 element with one flange diameter should not automatically be replaced by another size 42 version.

KTR BoWex Elastic 48

BoWex-ELASTIC 48 is available in several configurations. Current products include HE1/HE2 and HE3/HE4 executions with standard or SAE-related flange dimensions.

Examples include elements described with:

• HE1/HE2 Ø198
• HE1/HE2 Ø215.8 SAE6.5
• HE3/HE4 Ø241.3 SAE7.5
• T40, T50 or T65 Shore A hardness

This illustrates why the words “BoWex Elastic 48” alone are insufficient for ordering. The complete HE design, diameter, SAE size and Shore value must be checked.

KTR BoWex Elastic 65

BoWex-ELASTIC 65 elements are used in larger engine-driven power-transmission systems. AWELASTIC listings include HE1/HE2 and HE3/HE4 versions with different flange connections.

Examples represented in the catalogue include:

• HE1/HE2 Ø244
• HE3/HE4 Ø314.25 SAE10
• HE3/HE4 Ø352.3 SAE11.5
• T40, T50 and T65 Shore A versions, depending on the execution

The SAE10 and SAE11.5 elements are separate products and should not be considered interchangeable because they share the same nominal size.

KTR BoWex Elastic 80

BoWex-ELASTIC 80 is intended for higher-capacity drivetrain configurations. Available versions can differ by outside diameter, SAE flywheel connection and elastomer hardness.

Current product configurations include HE1/HE2 elements with standard and SAE11.5-related flange dimensions.

Before ordering, verify the complete product code, flange diameter, Shore hardness and matching hub specification.

KTR BoWex Elastic 100

BoWex-ELASTIC 100 is used in selected higher-power engine-driven applications. The larger nominal size does not remove the need to verify the complete mounting and drivetrain specification.

Check:

• The HE execution
• The SAE or special flange connection
• The actual outside diameter
• The internal tooth profile
• The matching hub dimensions
• The original Shore hardness
• The connected engine and driven equipment

A size 100 element should be selected from the complete technical description rather than nominal size alone.

BoWex Elastic HE1, HE2, HE3 and HE4 Types

BoWex-ELASTIC elements are manufactured in different HE executions. HE1, HE2, HE3 and HE4 identify different coupling configurations and axial arrangements.

Although two products may use the same nominal rubber element size, the complete coupling arrangement and connected hub can differ.

Before selecting an HE type, verify:

• The complete HE designation
• The installed axial arrangement
• The engine-side flange dimensions
• The driven-side BoWex hub
• The required installed length
• The available clearance inside the housing

Do not substitute HE1/HE2 and HE3/HE4 versions solely because they share the same element size or Shore hardness.

SAE Flywheel Connections

Many BoWex-ELASTIC flange elements are designed for engine-side connections corresponding with SAE J620 flywheel dimensions.

Product descriptions may include SAE references such as:

• SAE 6.5
• SAE 7.5
• SAE 10
• SAE 11.5
• SAE 14

The applicable SAE sizes depend on the nominal BoWex-ELASTIC size and HE execution.

Before selecting an SAE element, confirm:

• The flywheel SAE designation
• The actual flange outside diameter
• The bolt-hole quantity
• The bolt-circle diameter
• The flange thickness
• The axial mounting position
• The available housing clearance

Do not identify an SAE connection from one approximate dimension. Compare the complete mounting pattern and original product description.

Special BoWex Elastic Flange Dimensions

Not every BoWex-ELASTIC element is identified only by an SAE designation. Some products use special or application-specific outside flange dimensions.

When no SAE number is visible, accurately measure:

• The maximum outside diameter
• The flange pilot diameter
• The central opening
• The flange thickness
• The number and diameter of mounting holes
• The bolt-circle diameter
• The distance between the flange face and toothed connection

A photograph with measurement points clearly marked can help distinguish between visually similar elements.

KTR T40, T50 and T65 Shore Hardness

The Shore A value describes the hardness of the BoWex-ELASTIC rubber element and influences the torsional stiffness and vibration behaviour of the complete drivetrain.

The current AWELASTIC catalogue groups products under:

• KTR BoWex Elastic T40 ShA
• KTR BoWex Elastic T50 ShA
• KTR BoWex Elastic T65 ShA

Elements with identical outside dimensions can have different Shore hardness values and should not automatically be treated as interchangeable.

The correct Shore hardness is normally determined by the original coupling specification and the torsional requirements of the engine and driven equipment.

Why Shore Hardness Must Match the Original

A lower Shore A value generally represents a softer and more torsionally flexible element, while a higher value represents a stiffer elastomer execution.

Changing the hardness can alter:

• Torsional stiffness
• Vibration damping
• Drivetrain natural frequencies
• Shock-load response
• Angular movement under torque
• The dynamic loading of connected components

Do not select T40, T50 or T65 only according to availability or price. Retain the original value unless a different hardness has been technically confirmed for the complete drivetrain.

Identifying the Coupling by Internal Teeth

The internal teeth of the BoWex-ELASTIC element engage with the externally toothed BoWex hub. When the original description is unreadable, the tooth arrangement can provide valuable identification information.

Record:

• The exact number of internal teeth
• The internal major diameter
• The internal minor diameter
• The tooth width
• The depth of the toothed section
• The matching hub outside diameter
• All markings visible on the hub

The internal tooth count can help identify the probable coupling size, but it does not confirm the complete flange diameter, HE execution or Shore hardness.

Checking the Matching BoWex Hub

The elastic flange element and the BoWex hub form a matched drive connection. A correctly identified rubber element can still be unsuitable when the existing hub belongs to another size or execution.

Inspect the hub for:

• Complete KTR or BoWex markings
• The number and profile of external teeth
• Worn, chipped or deformed teeth
• The hub bore or spline dimensions
• The keyway dimensions
• The overall hub length
• The axial retaining arrangement
• Excessive rotational clearance

A new elastic element should not be installed over a severely worn or incorrectly sized hub.

BoWex Elastic Coupling Applications

BoWex-ELASTIC couplings are used in engine-driven systems exposed to torsional vibration and changing loads.

Typical applications can include connections between a diesel engine and:

• A generator
• A compressor
• A splitter gearbox
• A feed pump
• A high-pressure pump
• Industrial process equipment
• Marine or auxiliary drive equipment
• Mobile and stationary power units

The application type or machine model can help narrow the search, but it does not replace the original coupling designation. Similar machines may use different engines, flywheels, hubs or Shore hardness values.

Why Use Original KTR BoWex Elastic Elements?

An original KTR BoWex-ELASTIC element is manufactured for the defined dimensions, material characteristics, tooth geometry and torsional behaviour of the corresponding coupling system.

A visually similar alternative may differ in:

• Actual Shore hardness
• Dynamic torsional stiffness
• Rubber formulation
• Dimensional accuracy
• Internal tooth geometry
• Flange and bolt-hole dimensions
• Ageing and temperature behaviour
• Production traceability

These differences can affect fitment, vibration behaviour and the service life of the complete engine-driven system.

How to Recognise an Original KTR Component

When inspecting an existing or replacement element, look for:

• Clear KTR manufacturer identification
• The BoWex-ELASTIC product family name
• The complete nominal size and HE designation
• The SAE size or flange dimension
• The T40, T50 or T65 Shore hardness marking
• Production or traceability information
• Consistent moulding and finishing quality
• Dimensions matching the technical specification

A logo or similar external appearance alone does not confirm that an element is the correct original replacement for the installed drivetrain.

Signs of BoWex Elastic Coupling Wear

Inspect the coupling when the machine develops increased vibration, unusual drivetrain noise, irregular torque transmission or visible movement within the assembly.

Possible signs of wear or damage include:

• Cracks or splits in the rubber element
• Permanent deformation
• Hardening or loss of elasticity
• Separation around the flange or toothed connection
• Damaged or worn internal teeth
• Excessive rotational clearance
• Loose or damaged mounting bolts
• Heat-related deterioration
• Oil, fuel or chemical contamination
• Uneven wear caused by incorrect positioning

The reason for premature failure should be investigated before installing a new element. Repeated damage can indicate worn hubs, incorrect axial positioning, loose mountings, unsuitable Shore hardness or another drivetrain problem.

Inspecting the Complete Coupling Assembly

Do not inspect only the visibly damaged rubber element. Check the complete engine-to-machine connection.

Inspect:

• The externally toothed BoWex hub
• The internal teeth of the elastic element
• The engine flywheel and flange connection
• All mounting bolts and fastening components
• The hub bore, spline or keyway
• The axial position of the complete coupling
• The engine and driven-equipment mountings
• The alignment of the connected components
• Nearby components that could contact the coupling

A new element can be damaged prematurely when installed with a worn hub, damaged flywheel connection, loose machine mounting or incorrect axial position.

BoWex Elastic Installation and Alignment

Installation should follow the correct KTR assembly instructions for the specific element size and HE execution.

Before returning the equipment to service:

• Confirm the complete replacement description
• Check that the hub and element belong to the same size
• Verify the required axial installation position
• Inspect all teeth and connection surfaces
• Use the specified bolts and fastening method
• Follow the correct tightening sequence and torque values
• Confirm that the hub engages evenly with the element
• Check the engine and driven-machine supports
• Ensure that no component is forced into position

The coupling can compensate for specified drivetrain displacement, but it should not be used to correct major assembly errors, damaged supports or unsuitable engine-to-machine geometry.

Browse Original KTR BoWex Elastic Elements

Browse the complete range of original KTR BoWex Elastic coupling elements by nominal size, HE design, flange diameter and Shore hardness.

Individual product pages provide the complete product description, dimensions, photographs, stock information and ordering options.

The WooCommerce product category is intended for comparing and purchasing actual components, while this post category provides technical explanations, identification guidance and maintenance information.

Explore Other KTR Coupling Guides

Return to the complete KTR coupling catalogue to browse BoWex FLE-PA flanges, BoWex-ELASTIC elements, ROTEX spiders, BoWex M sleeves and related original components.

Each KTR coupling family has its own construction, identification method and intended application. BoWex-ELASTIC elements should not be confused with torsionally stiff BoWex FLE-PA flanges or BoWex M polyamide sleeves.

Expert KTR BoWex Elastic Identification Support

If the installed BoWex-ELASTIC element cannot be identified, send AWELASTIC the complete visible description, Shore hardness, measurements, internal tooth count, machine information and clear photographs.

The guides in this post category provide practical help with BoWex-ELASTIC size identification, HE type recognition, SAE flange selection, Shore hardness verification, wear inspection and original replacement element selection.