An AI report on this issue:
Fork Failure – Likely Root Cause Analysis (Assuming Third-Party Supplier Used by TanTan)
Following the failure pictured in this thread, I’ve examined both sides of the fork and would like to contribute a technical breakdown of likely causes. Based on the images and common carbon manufacturing practices, the failure appears to have originated internally and propagated rapidly under load — not due to external impact.
Key Observations:
• The failure occurred at the crown-leg junction — a known high-stress area during braking and compression.
• On the opposite leg, there’s clear evidence of buckling and laminate rupture, indicating a structural collapse rather than an isolated crack.
• The fractured edge shows signs of dry fiber and fraying, typical of resin starvation or poor resin impregnation.
• There’s no sign of crash damage, deep abrasions, or tire rub that might indicate impact-induced failure.
Most Likely Root Causes:
1. Resin Starvation or Poor Wet-Out
Some of the fractured zones appear to lack sufficient resin, which compromises fiber cohesion and structural strength. This is often due to inconsistent layup, inadequate vacuum pressure, or issues in resin application.
2. Delamination Due to Poor Layer Bonding
The visible peeling and frayed laminate suggest layers may have separated under stress. This can result from under-curing, improper consolidation, or temperature control issues during manufacture.
3. Crown-Leg Transition Weakness
This area is often difficult to mold uniformly, especially on molds reused heavily or not maintained correctly. Stress concentrations here would exploit any weakness in fiber orientation or bonding.
4. Manufacturing Quality Control Lapse
If TanTan uses a third-party frame/fork supplier (as is often the case), inconsistent quality control in the supply chain could allow defects like this to pass undetected — especially in lower-cost carbon production environments.
Additional Thoughts:
• This failure should not occur under normal riding loads, and it highlights the importance of proper QC, layup integrity, and resin content.
• If this was a one-off, it’s unfortunate. If others have similar forks, it might be worth proactively inspecting the crown-leg junction — particularly for signs of surface distortion or laminate stress.
• A post-failure ultrasonic or CT inspection would confirm voids or resin-poor zones, but visually this already looks like catastrophic laminate failure due to internal defects.
