Hub Failure — World Class 48H Flange

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"World Class" brand 48H front hub, flange failed at two spoke holes on one side and three spoke holes on the other.

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Flange tear-outs are at nearly the same position on both flanges. The rider reports the wheel was nearly true laterally, but had two significant radial bumps.

The third (rightmost) spoke in the set of three is still under tension, suggesting the principle failure was between two spokes, as on the other side.

Spokes exit flange holes at about 60° — neither radial nor fully tangent, but more tangent than radial. Due to the close spacing (many spokes, small flange), full tangent lacing is not possible.

Spoke tension at time of failure unknown. After failure, tension ranged from 700N at about 90° to the broken flanges; to about 1750N for spokes next to the broken flanges, and with tension about 1000-1200N opposite the broken flanges.

Total service at time of failure approximately 1,000 km. Rider weight approximately 160 kg (350 lb.).

Spokes are DT, and DT has had several spacings from elbow to head. A complaint against wide spacing is elbow failures, but wide spacing may also bend the flange more.