Bottom Bracket Bearing Failure

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2007 Campagnolo Record "UltraTorque"-model bottom bracket using 6805(?)-series outboard cartridge bearings. The right (chainring-side) bearing failed.

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Found via occasional "popping" sound. Crank is marked

Campagnolo
L 172.5
OB 715756
SN 1518

Hilly riding, typically slow pedaling/high-torque. Bike+rider approx 85 kgf. Approximately 1,000km use.

On disassembly, clamp bolt "felt tight" but was not checked with torque wrench.

It appears the bearings fractured in to small pieces that were able to escape from the cartridge without damage to either inner or outer race. In contrast, typical overload- and grit-induced failures cause bad bearing surface damage and eventual loose operation or race fracture.

The bearing is a Conrad-style offset-fill bearing. While some of the cage was ejected, it does not appear to have been enough to allow ball rearrangement and self-disassembly.

Metal debris was found in the bottom bracket but was not available for inspection.