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KTR BoWex Hubs

KTR BoWex Hubs: Identification, Dimensions and Technical Guides

Explore practical KTR BoWex hub guides for engineers, maintenance teams, machinery owners and spare-parts buyers. This technical knowledge section explains how to identify an installed BoWex coupling hub, interpret its markings, count the external teeth, measure the bore or spline and select the correct original replacement component.

KTR BoWex hubs are used with different curved-tooth coupling systems, including BoWex FLE-PA flange couplings, BoWex-ELASTIC elements and selected BoWex sleeve couplings. Although several hubs may appear similar, they can differ by coupling size, external tooth profile, internal spline, bore diameter, keyway, hub length and axial mounting arrangement.

The articles in this category focus on practical identification and inspection questions. Use them to collect the correct technical information before ordering and to avoid selecting a hub that fits the shaft but does not correspond with the installed coupling flange or element.

What Is a KTR BoWex Hub?

A KTR BoWex hub is the metal component that connects the coupling with the hydraulic pump shaft, gearbox shaft or another driven component.

Depending on the BoWex coupling design, the hub normally has:

• External curved teeth that engage with the coupling flange, elastic element or polyamide sleeve
• An internal cylindrical bore, spline, taper bore or application-specific shaft connection
• A keyway, clamping arrangement or axial retaining system
• A defined overall length and toothed engagement length
• A product marking, drawing number or coupling-size designation

The curved-tooth connection transfers torque while allowing limited axial, radial and angular displacement within the limits specified for the complete coupling system.

The hub must match both sides of the drivetrain: its external teeth must correspond with the coupling element, while its internal connection must correspond with the installed shaft.

How to Identify a KTR BoWex Hub

Correct identification should begin with the complete description stamped, engraved or printed on the hub.

Use the KTR BoWex hub identification guide to see which markings, measurements and photographs should be collected.

Clean the hub carefully and inspect the complete outer surface, front face and rear face. Dirt, corrosion, grease or the installed position may conceal part of the description.

Look for information such as:

• KTR or KTR-Kupplungstechnik manufacturer identification
• BoWex product-family marking
• The nominal coupling size
• PB-S, PB-BS, T or another hub execution
• A KTR product or drawing number
• The bore, spline or shaft specification
• Production or traceability markings
• An older Rheine manufacturing address

Copy the complete marking exactly as it appears. Do not omit letters, hyphens or suffixes, because they may identify a different hub length, bore or mounting arrangement.

Understanding KTR BoWex Hub Markings

Existing BoWex hubs can carry descriptions such as:

• KTR BoWex 42 PB-S
• KTR BoWex 42 PB-BS
• BoWex T80
• A KTR drawing or product number

The numerical part commonly helps identify the coupling size, while the letters describe a particular hub or mounting execution.

Do not interpret a partial marking as a complete order code. Two hubs carrying the same nominal BoWex size may still have different:

• Internal bores or splines
• Overall lengths
• Toothed engagement lengths
• Keyways
• Axial retaining arrangements
• Short or extended hub designs

When the meaning of a suffix is uncertain, compare the hub with the corresponding KTR drawing rather than selecting a replacement from the size alone.

Information Required Before Ordering

Before requesting a replacement KTR BoWex hub, collect all available information from the existing coupling and the complete machine.

Please provide:

• The complete description visible on the hub
• The KTR product or drawing number
• The nominal BoWex coupling size
• The number of external hub teeth
• The outside diameter across the external teeth
• The toothed section width
• The complete hub length
• The internal bore or spline dimensions
• The number of internal spline teeth
• The spline major and minor diameters
• The keyway width and depth, where applicable
• The shaft diameter
• The axial retaining arrangement
• The matching FLE-PA flange, BoWex-ELASTIC element or sleeve size
• The engine manufacturer and model
• The hydraulic pump, gearbox or driven-equipment model
• The machine manufacturer, model and serial number
• Clear photographs of every side of the hub
• A photograph of the complete installed coupling assembly

The original hub description or drawing number should be used as the main identification reference whenever it remains available. Measurements, tooth counts and machinery information should provide additional confirmation.

Identifying a Hub by Its External Teeth

The external curved teeth engage with the internal teeth of the corresponding BoWex coupling flange, elastic element or polyamide sleeve.

When the product marking is unavailable, count the external teeth carefully. Mark the first tooth before counting to avoid including it twice.

Also record:

• The number of external teeth
• The maximum outside diameter across the teeth
• The root diameter between the teeth
• The individual tooth width
• The axial length of the toothed section
• The direction and form of the curved-tooth profile
• Visible wear or damage on the tooth surfaces

The external tooth count can help identify the probable coupling size, but it is not always unique. Different BoWex sizes or product families may use similar tooth counts, so the bore, hub length and matching coupling component must also be checked.

Matching the Hub with a BoWex FLE-PA Flange

A BoWex FLE-PA coupling combines a fibre-reinforced polyamide flange with a steel hub featuring external curved teeth.

The hub and flange must correspond with the same BoWex tooth system. A hub that fits the hydraulic pump shaft can still be incorrect if its external teeth do not match the FLE-PA flange.

Use the KTR BoWex FLE-PA flange identification guide to identify the matching flange size, internal tooth count and outside diameter.

Before combining the components, confirm:

• The nominal BoWex size of both parts
• The flange internal tooth count
• The hub external tooth count
• The corresponding tooth dimensions
• The required engagement length
• The correct axial hub position
• The hydraulic pump shaft connection

Do not force a hub into a flange when the teeth do not engage smoothly. Resistance can indicate an incorrect size, damaged teeth, contamination or an unsuitable axial position.

BoWex FLE-PA Hub Sizes

KTR BoWex FLE-PA systems are available in several nominal sizes. AWELASTIC currently groups the main original flanges under the following product ranges:

• KTR BoWex 48 FLE-PA
• KTR BoWex 65 FLE-PA
• KTR BoWex 80 FLE-PA
• KTR BoWex 100 FLE-PA
• KTR BoWex 125 FLE-PA

Additional BoWex sizes may be used in particular machinery configurations. The correct hub must be selected from the installed component, original drawing or complete drivetrain specification rather than from this list alone.

Matching the Hub with a BoWex-ELASTIC Element

BoWex-ELASTIC couplings use a highly flexible circular element with an internally toothed axial connection. The matching BoWex hub is inserted into this internal connection.

Use the KTR BoWex-ELASTIC identification guide to identify the element size, HE execution, flange dimensions and Shore hardness.

The hub must correspond with:

• The nominal BoWex-ELASTIC element size
• The element’s internal tooth profile
• The HE1, HE2, HE3 or HE4 coupling arrangement
• The required axial installation length
• The shaft or spline of the driven equipment
• The complete engine-to-machine configuration

Shore hardness identifies the elastic element, not the steel hub. However, the hub and element must still form the correct matched coupling assembly.

BoWex Hubs with Cylindrical Bores

Some KTR BoWex hubs use a finished cylindrical bore for mounting on a standard shaft.

When identifying a cylindrical-bore hub, measure:

• The exact finished bore diameter
• The bore tolerance, where available
• The total bore depth
• The shaft engagement length
• The keyway width and depth
• The location of the keyway relative to the external teeth
• The setscrew thread and position
• The overall hub length

Do not measure only the accessible front edge of a worn bore. Take several measurements along the full bore to check for taper, damage or uneven wear.

BoWex Hubs with Keyways

A keyed hub transfers torque between the shaft and hub through a corresponding shaft key and keyway.

Before ordering a keyed hub, verify:

• The finished bore diameter
• The keyway width
• The keyway depth
• The shaft-key dimensions
• The position of the keyway
• The setscrew location
• The required hub length
• The original shaft tolerance

A hub with the correct bore diameter but an incorrect keyway can be impossible to install or unsuitable for reliable torque transmission.

The replacement should follow the original shaft and key specification rather than being modified without appropriate engineering confirmation.

BoWex Hubs with Internal Splines

Many hydraulic pump applications use a splined BoWex hub rather than a plain cylindrical bore.

Internal spline identification requires more than measuring the central opening. Please record:

• The exact number of internal spline teeth
• The spline major diameter
• The spline minor diameter
• The tooth thickness
• The spline engagement length
• Whether any teeth are intentionally removed or modified
• The matching pump-shaft tooth count
• The hydraulic pump manufacturer and model

If some hub teeth are cut away or difficult to count, inspect the matching shaft and compare its complete spline profile.

A hub should not be selected solely from the number of spline teeth. Different spline standards can share the same tooth count while having different diameters, pressure angles or tooth profiles.

Taper and Inch-Bore BoWex Hubs

KTR also supplies BoWex hubs with taper bores, inch bores and application-specific connections for hydraulic pumps and industrial machinery.

For these hubs, provide:

• The original KTR description or drawing number
• The nominal taper or inch size
• The small and large bore diameters
• The taper length
• The keyway or spline details
• The retaining-nut, washer or screw arrangement
• The pump or shaft manufacturer
• The full driven-equipment model

Do not replace a taper-bore or inch-bore hub with a visually similar metric component without confirming the complete connection specification.

Plain and Unmarked BoWex Hubs

When the hub has no readable marking, identification must be based on its complete physical specification.

Measure and photograph:

• The number of external teeth
• The maximum outside diameter
• The external tooth-root diameter
• The toothed-section width
• The overall hub length
• The flange or shoulder diameters
• The internal bore or spline
• The keyway dimensions
• The retaining features
• The original installed orientation

Place a ruler or calliper clearly within the photograph, but also provide the measurements separately. Perspective distortion can make dimensions taken from photographs unreliable.

Short and Long Hub Executions

BoWex hubs can be produced with different total lengths and shaft-engagement arrangements.

A short and long hub may share the same external tooth system while differing in:

• Overall hub length
• Bore or spline engagement length
• Axial position relative to the flange
• Distance between the pump face and coupling element
• Location of the retaining screw or plate
• Available clearance inside the bell housing

Selecting the wrong length can result in incomplete tooth engagement, contact with surrounding components or an incorrect engine-to-pump installation distance.

Always measure the existing hub before removal and record its orientation within the coupling assembly.

Correct Axial Tooth Engagement

The hub’s external teeth must engage with the coupling element over the axial length specified for the particular BoWex system.

Insufficient engagement can concentrate the transmitted load over a limited tooth area and accelerate wear. Excessive insertion can cause unwanted contact or prevent correct assembly.

Before operation, verify:

• The hub’s axial installation position
• The available tooth-engagement length
• The original retaining arrangement
• The distance between connected components
• The absence of contact with the flange or housing
• The correct orientation of asymmetric hubs

Use the appropriate KTR assembly drawing and instructions for the exact coupling configuration.

Signs of KTR BoWex Hub Wear

Inspect the hub when the machine develops unusual drivetrain noise, increased rotational clearance, vibration or repeated damage to the matching flange or elastic element.

Possible signs of hub wear include:

• Rounded or thinned external teeth
• Chipped or broken tooth edges
• Uneven contact marks across the tooth width
• Excessive rotational backlash
• Worn internal splines
• An enlarged or damaged bore
• A worn or deformed keyway
• Cracks around the bore or hub shoulder
• Corrosion or fretting marks
• Movement on the connected shaft
• Heat discolouration
• Damage to the retaining components

A new flange or coupling element should not be installed on a severely worn hub.

Common Causes of Hub and Tooth Damage

Hub damage can result from normal wear, but it can also indicate an installation or drivetrain problem.

Possible causes include:

• An incorrect BoWex hub or coupling size
• Insufficient external-tooth engagement
• An incorrect axial installation position
• Excessive shaft displacement
• A loose hub or damaged retaining system
• A worn shaft spline or keyway
• Incorrect engine or pump mounting
• Overload or repeated shock loading
• Contamination between the tooth surfaces
• Forced assembly of incompatible components
• Movement in the hydraulic pump or engine supports

The cause of premature wear should be identified before fitting the replacement part. Otherwise, the new hub, flange or elastic element may fail again.

Inspect the Complete BoWex Coupling Assembly

Do not inspect only the visibly damaged hub. Check the complete connection between the engine and driven equipment.

Inspect:

• The corresponding FLE-PA flange, BoWex-ELASTIC element or sleeve
• All internal and external coupling teeth
• The pump or gearbox shaft
• The shaft spline or keyway
• The axial retaining components
• The engine flywheel connection
• The pump mounting flange
• The engine and driven-equipment supports
• The axial position of the complete coupling
• The available housing clearance

A worn or incorrectly mounted connected component can damage a new original BoWex hub.

Why Use an Original KTR BoWex Hub?

An original KTR BoWex hub is manufactured for the specified tooth profile, dimensions, bore or spline geometry and operating requirements of the corresponding coupling system.

A visually similar replacement may differ in:

• External curved-tooth geometry
• Tooth width and engagement length
• Steel grade and heat treatment
• Bore or spline accuracy
• Keyway dimensions
• Concentricity and rotational balance
• Overall installation length
• Surface finish
• Production consistency and traceability

These differences can affect fitment, load distribution and the service life of the complete coupling assembly.

How to Recognise an Original KTR Hub

When inspecting an existing or replacement hub, look for:

• Clear KTR or KTR-Kupplungstechnik identification
• The BoWex product-family name
• The complete nominal size and execution
• A KTR product or drawing number
• Accurately manufactured curved teeth
• Correct bore, spline or keyway dimensions
• Consistent machining and surface finish
• Traceable technical information

A similar external shape or matching tooth count alone does not confirm that the hub is original or suitable for the installed drivetrain.

BoWex Hub Applications

KTR BoWex hubs are used in mechanical engineering, hydraulic drives and engine-driven power-transmission systems.

Typical applications can include:

• Hydraulic pumps
• Diesel-engine power units
• Construction machinery
• Forestry equipment
• Agricultural machinery
• Mobile cranes
• Compressors
• Generators
• Splitter gearboxes
• Industrial pumps
• Rail and maintenance equipment
• Stationary hydraulic systems

The machine model can help narrow the search, but it does not replace verification of the original hub, coupling and shaft specifications.

KTR BoWex Technical Data and Downloads

Technical documentation can help confirm hub dimensions, coupling sizes, mounting arrangements, tooth engagement and installation requirements.

Visit the KTR BoWex FLE-PA catalogues and assembly instructions page to access available technical information.

Use documentation corresponding with the exact coupling type and size. General BoWex product-family information should not be applied automatically to every hub execution.

Browse Original KTR Coupling Components

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

For engine-to-pump flange couplings, browse the KTR BoWex FLE-PA product range.

For highly flexible engine-driven applications, browse the original KTR BoWex-ELASTIC elements.

The WooCommerce product categories are intended for comparing and purchasing components, while this post category provides hub identification, measurement and inspection guidance.

Explore Other KTR Identification Guides

Additional AWELASTIC technical resources include:

• KTR BoWex FLE-PA flange identification
• KTR BoWex-ELASTIC identification
• KTR ROTEX spider identification

Each KTR coupling family has its own identification method. A BoWex hub should always be matched with the exact flange, sleeve or elastic element used in the installed assembly.

Expert KTR BoWex Hub Identification Support

If the installed hub cannot be identified, send AWELASTIC the complete visible markings, external and internal tooth counts, bore or spline measurements, overall length, machine details and clear photographs.

The articles in this post category provide practical assistance with KTR BoWex hub markings, external tooth identification, spline measurement, flange compatibility, wear inspection and original replacement-hub selection.