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one check Pego195 could make which could potentially advance the investigation would be to look at the outer face of the cycle's Stronglight fixed bottom bracket cup
it will either be one ring and eight sides which equals metric thread or no ring and eight sides whidch equals Swiss thread
a Swiss threaded shell would
tend to support the idea of a MB origin for the bicycle while a metric threaded shell would not rule it out
above: Stronglight metric thread bottom bracket on a MB Grand Jubile model cycle
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