Originally Posted by
SkyDog75
Some French bottom bracket cups, like the ones that came on my '72 Peugeot UO-8, had "thin walls". Because of how thin they were, you'd need to use a spindle meant for a 70 mm bottom bracket even though the bike's shell was 68 mm. Otherwise the adjustable cup would thread in so far you couldn't fit the lockring.
Unlike most other manufacturers, Stronglight used the same spindle for all shell widths, and used a thicker cup for the wider 70mm Italian shell.