🛠 1. Improper Axial Installation

One of the top causes of failure is incorrect axial positioning of the coupling hub and flange. If the hub is not properly seated within the flange, the curved-tooth geometry is compromised. This leads to:

• Uneven load distribution
• Premature wear of the polyamide teeth
• Axial thrust that the coupling wasn’t designed to absorb

Solution: Always follow the official KTR assembly instructions and check for full seating before fastening.

🛠 2. Misalignment Between Engine and Pump

While BoWex FLE-PA can tolerate some angular and axial misalignment, it is not a flexible coupling in the elastic sense. Excessive misalignment causes:

• Abnormal wear on gear teeth
• Tooth breakage
• Noise, vibration, and shortened coupling life

Tip: Align the engine and pump shafts within KTR’s specified tolerances. Use feeler gauges and dial indicators if necessary.

🛠 3. Incorrect Tightening Torque

Using the wrong torque on mounting screws can lead to:

• Loosening under vibration
• Flange cracking (especially in smaller sizes)
• Deformation of the curved-tooth engagement

Tip: Use proper torque values as specified in the manual. We supply the correct OEM screw sets for each size.

🛠 4. Thermal Overload

Although the flange is made from durable PA6-GF25 (glass fiber reinforced polyamide), overheating can deform the material or degrade long-term strength. Causes include:

• Operating in sealed engine compartments with poor airflow
• Prolonged high-load duty cycles
• Engine exhaust routing too close to the coupling

Recommendation: Use heat shields or provide ventilation. Check your application environment against KTR’s temperature limits.

🛠 5. Using Non-Original Parts

Couplings that do not bear the markings:

BoWex® XX FLE-PA | KTR-Kupplungstechnik | >PA6-GF25< | D-4440 Rheine

…are most likely aftermarket copies.

These replicas may look similar but often:

• Use lower-grade plastic compounds
• Have imprecise tooth geometry
• Lack the same dimensional tolerances or thermal properties

Bottom line: OEM parts last longer, fit correctly, and reduce risk of breakdown.