Carbon doesn't break like metal
A steel fork bends before it breaks — you get a warning. A carbon fork can look perfectly intact yet have suffered structural damage invisible to the naked eye. That's what makes regular inspection absolutely critical on carbon components.
Carbon is a composite: carbon fibers embedded in epoxy resin. Strength comes from fiber orientation (layup). An impact can break fibers or delaminate resin layers without the outer surface showing much.
Visual inspection — the foundation
Perform this inspection at least once a month, and systematically after any impact (crash, collision, curb strike).
Critical zones:
- Base of the steerer tube: this is the maximum stress zone. Look for cracks, paint chips, or unusual lines
- Junction between fork blades and crown: carefully examine the joints between the fork tubes and the upper section
- Dropouts: check the carbon integrity around metal inserts
- Blade surfaces: run your hand slowly along the full length. You're feeling for bumps, dents, soft spots, or texture variations
What's serious:
- Visible crack in the carbon (even hairline, even under clear coat) → replace
- Soft spot to the touch (healthy carbon is hard and resonant) → replace
- Whitish discoloration around an impact zone → possible delamination → professional inspection
- Deep chip that has penetrated through the gelcoat to the fibers → professional inspection
What's cosmetic:
- Small surface scratches in the clear coat
- Paint chips that don't penetrate the fibers
- Cable rub marks
The tap test — its limitations
The "coin tap test" involves tapping the fork with a coin and listening. Healthy carbon produces a clear, sharp sound. Damaged carbon produces a dull or dead sound.
Caution: this test is a first indicator, not a diagnosis. It doesn't detect all types of damage, particularly deep delaminations. It can also give false positives in areas of variable thickness (crown, junctions). Don't use it as your sole decision criterion — it's a complement to visual inspection.
