ON Cloud 5 and Cloud 6: Structural Failure Diagnosis
Generated by ReeFix AI · Sources: technical and specialist documentation (see Sources section)
Revision of 17/08/2026
⚠️ DISCLAIMER: This diagnosis is for informational purposes only. The handling of chemical adhesives and solvents for shoe repair must be carried out in adequately ventilated environments and with the aid of personal protective equipment.
OBSERVED SYMPTOMS
The defect manifests as a tear or structural failure of the upper mesh, typically located in the forefoot area, at the metatarsophalangeal joints. The following symptoms may be observed:
| Symptom | Detailed Description |
|---|---|
| Visible tear | A rip in the fabric, often with frayed threads, progressing from a thinning of the weave to a macroscopic break. |
| Specific location | The tear predominantly occurs where the shoe flexes during gait (the natural "flex point" of the forefoot) or at the edges of heat-sealed TPU reinforcements. |
| Internal wear | In some cases, the damaged area may show fabric thinning or internal roughness before the tear. |
| Symmetry | The tear may be present on both shoes in similar positions, suggesting a mechanical fatigue issue. |
WHAT TO RULE OUT
For an accurate analysis, it is crucial to rule out some less probable causes or those that would require a different approach:
- Acute external impact damage: If the tear is clean, linear, and does not show frayed filaments but rather a cut, or if there are clear signs of external abrasion on the sole or protective profiles, the cause could be an accidental impact or cut, not an internal structural failure.
- Generalized manufacturing defect: If the damage appears on only one shoe or in an unusual spot not related to flexing, an intrinsic design defect of the model is less likely, and an external factor or localized wear is more probable.
- Asymmetrical CloudTec sole collapse: Check that the cushioning elements ("clouds") of the sole are not excessively collapsed or unevenly worn, which could induce abnormal twisting on the upper. If the sole is intact, the cause is almost certainly in the upper.
- Healthy adjacent materials: If the fibers around the tear are still robust and show no signs of "pilling" or extensive thinning, the repair is more straightforward.
FINAL CAUSE
The structural failure of the mesh in ON Cloud 5 and Cloud 6 is predominantly due to a mix of mechanical stress and friction, with varying probabilities:
| Probability | Cause | Why | Key Signal | Quick Check | Often Happens When |
|---|---|---|---|---|---|
| 45% | Mechanical fatigue from cyclic flexing | The polyester mesh, designed for lightness and breathability, is subjected to repeated tensions during the foot's push-off phase. Areas where the fabric changes density create stress concentration points, leading to progressive failure. | Symmetrical tear at the natural flex point of the forefoot, with frayed threads but no signs of external impact. | Put on the shoe and flex the forefoot: the tear is exactly where the fabric bends most. | The shoe is used intensively for running or prolonged walking, accumulating thousands of flexion cycles. |
| 30% | Localized internal friction | Continuous rubbing of toes (especially big toe or pinky), untrimmed nails, or socks with thick seams acts as an abrasive on the inner wall of the mesh, weakening it. An imperfect fit (e.g., wide foot or high instep) also increases internal pressure. | Localized wear primarily on the medial (big toe) or lateral (pinky) side, with fabric thinning before rupture. | Inspect the inside of the upper in the affected area for roughness or wear of the inner lining. | N/A |
| 15% | Delamination and cutting from heat-sealed TPU edge | The junction between the flexible mesh and rigid TPU reinforcements creates a virtual cutting line. Repeated flexing of the shoe pushes the mesh against the rigid edge of the TPU, accelerating the rupture. | A clean, linear cut that precisely follows the profile of the heat-sealed plastic reinforcement on the upper. | Carefully analyze the junction edge between the TPU and the mesh. | N/A |
| 10% | Minor causes: external abrasion or yarn defect | Micro-dust or debris infiltrating the mesh can act as abrasives. Rarely, a yarn defect can lead to premature failure. | Asymmetrical tears, visible scratches on the sole or protective profiles indicating external contact, or sudden failure without progressive wear. | N/A | N/A |
Tools for Repair (if you decide to act):
- For DIY repair (medium difficulty):
- Adhesive repair patches for ON Cloud shoes (microfiber or nylon).
- Use of a flexible polyurethane shoe glue (specific adhesive for athletic footwear).
- Insertion of a wooden shoe stretcher to maintain the correct upper shape during drying.
- For professional intervention (high difficulty):
- In addition to the above, a specialized cobbler might apply a TPU heat-seal reinforcement tape for external heat-sealing, using specific hot-bonding equipment.
Operational Decision:
If the tear is symmetrical in the flex zone (45-30% probability), you can attempt a DIY repair with adhesive patches and specific glue (parts cost approximately €10-20). If the damage is clean and localized near the TPU reinforcement (15% probability), or if you prefer not to risk it, we recommend consulting a specialized cobbler for professional intervention (estimated labor cost of €25-45). If the mesh wear is extensive throughout the upper and the shoes have accumulated many kilometers, complete replacement remains the most suitable choice.
Remember that for this type of adhesive, drying time and strong initial pressure are crucial: before joining the parts, let the solvent evaporate for about 10-15 minutes until the glue is almost dry to the touch, then press firmly.
ReeFix provides this diagnosis EXCLUSIVELY for educational and informational purposes.
Why do my ON Cloud 5 or Cloud 6 break on the upper in the forefoot?
The mesh failure is due to mechanical fatigue at the shoe's natural flex point or at the edges of the TPU reinforcements.
How to recognize structural mesh failure in ON Cloud shoes?
It manifests as tears, frayed filaments in the forefoot, thinning of the fabric, or internal wrinkling, often symmetrically.
When to contact a professional to repair ON Cloud 5 or 6?
Contact a shoemaker if the tear is near the TPU reinforcements or if you prefer a durable professional repair.
This diagnostic report is generated using an artificial intelligence system (RAG) based on the aggregation of online data. The moderation by Luca Chia (Electronic Expert) validates its logical coherence and technical plausibility regarding the described symptoms, confirming the correctness of the AI's diagnostic reasoning, without however constituting an absolute guarantee of resolution for individual cases.